Hi,
For a lightweight server based on a Pi 3 or 4, the recommendation was
to use an externally powered USB hard drive (rather than powering it
from the Pi's USB port) for better reliability.
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
Thanks.
For a lightweight server based on a Pi 3 or 4, the recommendation was
to use an externally powered USB hard drive (rather than powering it
from the Pi's USB port) for better reliability.
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
Adam Funk wrote:
For a lightweight server based on a Pi 3 or 4, the recommendation was
to use an externally powered USB hard drive (rather than powering it
from the Pi's USB port) for better reliability.
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
Do they actually use less? The T5 spec says 4 Watts, I can see Tom's hardware measured a spinning 500GB Samsung USB at 2.7 Watts ... OK one
of those is a spec, the other is as measured ...
Do they actually use less? The T5 spec says 4 Watts, I can see Tom's hardware measured a spinning 500GB Samsung USB at 2.7 Watts ... OK one
of those is a spec, the other is as measured ...
Adam Funk wrote:
For a lightweight server based on a Pi 3 or 4, the recommendation was
to use an externally powered USB hard drive (rather than powering it
from the Pi's USB port) for better reliability.
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
Do they actually use less? The T5 spec says 4 Watts, I can see Tom's hardware measured a spinning 500GB Samsung USB at 2.7 Watts ... OK one
of those is a spec, the other is as measured ...
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
On 14/07/2021 10:16 am, Andy Burns wrote:
Adam Funk wrote:
For a lightweight server based on a Pi 3 or 4, the recommendation was
to use an externally powered USB hard drive (rather than powering it
from the Pi's USB port) for better reliability.
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
Do they actually use less? The T5 spec says 4 Watts, I can see Tom's
hardware measured a spinning 500GB Samsung USB at 2.7 Watts ... OK one
of those is a spec, the other is as measured ...
That's when it is spinning - the startup current is (can be) more of a problem.
Having said that, I have a 4TB drive connected to a Pi4 without external power but a 5TB drive requires an extra 5V supply.
Also (second-hand) 250GB M2 drive in M2-USB3 converter case.
Andy Burns <usenet@andyburns.uk> wrote:
Do they actually use less? The T5 spec says 4 Watts, I can see Tom's
hardware measured a spinning 500GB Samsung USB at 2.7 Watts ... OK one
of those is a spec, the other is as measured ...
Typically the flash will use a lot less when idling. Both will take more power when being accessed, but the HDD still needs to spin while the SSD can sleep. The HDD could spin down but then the access time when it needs to power up again is measured in seconds.
On 14-07-2021 10:18, Adam Funk wrote:
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
Yes. Works perfectly for me, no trouble for years with a T5.
Andy Burns wrote:
The T5 spec says 4 Watts
Where did you find the specs for the USB SSDs?
Adam Funk wrote:
Where did you find the specs for the USB SSDs?
<https://www.samsung.com/semiconductor/global.semi.static/Samsung_Portable_SSD_T5_User_Manual_v0.0_Rev01_English.pdf>
5V 0.8A
On 2021-07-14, A. Dumas wrote:
Yes. Works perfectly for me, no trouble for years with a T5.
Thanks. (I didn't know USB SSDs had been around for years.)
Yebbut.... no details whatsoever. Is that max on startup, max in use,
typical while reading, writing? Etc. It seems quite high; mine doesn't get warm which I would expect at constant 4 W.
I'd expect the difference between running and start-up currents to be
a lot less for an SSD than a drive with a motor --- is that correct?
https://www.anandtech.com/show/11719/samsung-portable-ssd-t5-review-64layer-vnand-debuts-in-retail/4
bearing in mind they might have altered the internals since 2017, but it gives a guide. I note the spikes up to 3.5W which would accord with a PSU rating of 4W.
A. Dumas wrote:
It seems quite high; mine doesn't get
warm which I would expect at constant 4 W.
My M.2 NVMe in a cast aluminium soap-on-a-rope gets pretty hot ...
Hi,
For a lightweight server based on a Pi 3 or 4, the recommendation was
to use an externally powered USB hard drive (rather than powering it
from the Pi's USB port) for better reliability.
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
Andy Burns wrote:
<https://www.samsung.com/semiconductor/global.semi.static/Samsung_Portable_SSD_T5_User_Manual_v0.0_Rev01_English.pdf>
Yebbut.... no details whatsoever. Is that max on startup, max in use,
typical while reading, writing? Etc. It seems quite high; mine doesn't get warm which I would expect at constant 4 W.
…
That's when it is spinning - the startup current is (can be) more of a problem.
…
Chris Elvidge <chris@mshome.net> wrote:
…
That's when it is spinning - the startup current is (can be) more of a
problem.
…
As an extreme case, I remember a washing machine sized 100MB disk drive on
a VAX minicomputer I managed in the early 1980s, which took 240V three
phase power and drew some 100 amps for the first second until the magnetic field and the back emf built up in the motor windings. We had to fit a slow-blow fuse to the circuit to prevent it failing on switch-on.
We have come a long way since
to reach a couple of amps on 5V for a disk of
10,000 x the capacity and a minute fraction of the cost.
Adam Funk <a24061@ducksburg.com> wrote:
I'd expect the difference between running and start-up currents to be
a lot less for an SSD than a drive with a motor --- is that correct?
Definitely.
On 14/07/2021 09:18, Adam Funk wrote:
Hi,
For a lightweight server based on a Pi 3 or 4, the recommendation was
to use an externally powered USB hard drive (rather than powering it
from the Pi's USB port) for better reliability.
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
I've used an SSD with Pi 3Bs, 3B+s and 4Bs. As long as you use a good
power supply, the Pi can drive these with no issues.
On 2021-07-14, druck wrote:
On 14/07/2021 09:18, Adam Funk wrote:
Hi,
For a lightweight server based on a Pi 3 or 4, the recommendation was
to use an externally powered USB hard drive (rather than powering it
from the Pi's USB port) for better reliability.
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
I've used an SSD with Pi 3Bs, 3B+s and 4Bs. As long as you use a good
power supply, the Pi can drive these with no issues.
As it happens, I'm going to try it with a 2B because I have a spare
one lying around. But the documentation shows the same 1.2A max total
USB draw for 2B, 3B, 3B+, and 4B.
My only concern now is using the keyboard and mouse for the initial
set-up (it will be used headlessly after that) --- I'll probably use a powered USB hub for that.
As an extreme case, I remember a washing machine sized 100MB disk drive
on a VAX minicomputer I managed in the early 1980s, which took 240V three
We have come a long way since to reach a couple of amps on 5V for a disk
of 10,000 x the capacity and a minute fraction of the cost.
Andy Burns <usenet@andyburns.uk> wrote:
A. Dumas wrote:
It seems quite high; mine doesn't get
warm which I would expect at constant 4 W.
My M.2 NVMe in a cast aluminium soap-on-a-rope gets pretty hot ...
Yes! I recently swapped such a drive in an old Macbook (where this was
still possible) and put the old one in an external enclosure; it gets quite hot just from being plugged in. But the T5s don't.
Adam Funk wrote:
Andy Burns wrote:
The T5 spec says 4 Watts
Where did you find the specs for the USB SSDs?
<https://www.samsung.com/semiconductor/global.semi.static/Samsung_Portable_SSD_T5_User_Manual_v0.0_Rev01_English.pdf>
5V 0.8A
As it happens, I'm going to try it with a 2B because I have a spare one
lying around. But the documentation shows the same 1.2A max total USB
draw for 2B, 3B, 3B+, and 4B.
On 14/07/2021 22:03, A. Dumas wrote:
Andy Burns <usenet@andyburns.uk> wrote:
A. Dumas wrote:
It seems quite high; mine doesn't get
warm which I would expect at constant 4 W.
My M.2 NVMe in a cast aluminium soap-on-a-rope gets pretty hot ...
Yes! I recently swapped such a drive in an old Macbook (where this was
still possible) and put the old one in an external enclosure; it gets quite >> hot just from being plugged in. But the T5s don't.
A quick look at the M.2 specs seems to have them between 2 and 7 watts.
Quite a bit higher than the SATA standard at about 2-3 watts. But 7
watts would be something to look out for with a rPi being 1.4 amps on USB.
I think if I were in the market for another drive I would go for a NVMe
in a USB adapter rather than a T5. I tend to rotate old parts and a NVMe drive is more flexible.
I can just about see the use of a T5 if it were something to put in a
pocket and carry around, but for any thing more static I would just use
a standard drive and an adapter.
So what advantage did you see in the T5?
IOW, be guided by the power supply capability of your wall rat, powered
hub, or whatever.
On Thu, 15 Jul 2021 08:46:24 +0100, Adam Funk wrote:
As it happens, I'm going to try it with a 2B because I have a spare oneI think that's a standard current draw limit as defined by the USB
lying around. But the documentation shows the same 1.2A max total USB
draw for 2B, 3B, 3B+, and 4B.
standard. In practise its a minimum: i.e. anything capable of supplying
power over USB 2 or 3 connections will provide at least 1.5 amps (it was
0.5A for USB 1).
For a data cable, USB 2 is spec'd to only provide a max of 0.5A(five
0.1A "units"). USB 3 was spec'd for 0.9A (six 0.15A "units"). USB 3.2 is spec'd for 1.5A.
USB-C cables are spec'd for 1.5A or 3A loads.
Power-only cables and charging-only ports are 1.5A (v1.1), and 5A (v1.2).
https://en.wikipedia.org/wiki/USB#Power
Chris Elvidge <chris@mshome.net> wrote:
That's when it is spinning - the startup current is (can be) more of a
problem.
As an extreme case, I remember a washing machine sized 100MB disk
drive on a VAX minicomputer I managed in the early 1980s, which took
240V three phase power and drew some 100 amps for the first second
until the magnetic field and the back emf built up in the motor
windings. We had to fit a slow-blow fuse to the circuit to prevent
it failing on switch-on.
We have come a long way since to reach a couple of amps on 5V for a
disk of 10,000 x the capacity and a minute fraction of the cost.
How much current the USB port can deliver is a function of
what is powering the Pi until the circuit board traces from PSU to USB
catch fire and fuse...
The Natural Philosopher wrote:
How much current the USB port can deliver is a function of what is
powering the Pi until the circuit board traces from PSU to USB catch
fire and fuse...
I thought there was actually a polyfuse in there somewhere?
These limits are amazingly badly defined: I looked at several sites that claimed to describe the USB standards, none of them entirely clear and
not all agreeing with each other. This is why I think its probably good enough to check that your power source has enough output to meet the requirements of what its meant to power and assume that the conductors in
the cable
the current carrying capacity implied by the lowest rated USB connector
on the cable [1].
[1] probably a dodgy assumption for el cheapo USB cables, so avoid those.
Hi,
For a lightweight server based on a Pi 3 or 4, the recommendation was
to use an externally powered USB hard drive (rather than powering it
from the Pi's USB port) for better reliability.
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
Thanks.
On 15/07/2021 19:44, Martin Gregorie wrote:
It isn't the current carrying capacity so much as the drop in volts
On 14/07/2021 09:18, Adam Funk wrote:
Hi,
For a lightweight server based on a Pi 3 or 4, the recommendation was
to use an externally powered USB hard drive (rather than powering it
from the Pi's USB port) for better reliability.
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
I've used an SSD with Pi 3Bs, 3B+s and 4Bs. As long as you use a good
power supply, the Pi can drive these with no issues.
On 2021-07-14, Paul Hardy <p.g.hardy@btinternet.com> wrote:
Chris Elvidge <chris@mshome.net> wrote:
That's when it is spinning - the startup current is (can be) more of a
problem.
As an extreme case, I remember a washing machine sized 100MB disk
drive on a VAX minicomputer I managed in the early 1980s, which took
240V three phase power and drew some 100 amps for the first second
until the magnetic field and the back emf built up in the motor
windings. We had to fit a slow-blow fuse to the circuit to prevent
it failing on switch-on.
The washing-machine drives I worked with in the 1970s (25MB) had
interlocks built into the motor circuits so if you punched the
ON button on more than one at a time it would sequence them so
that one drive was up to speed before the next started.
We have come a long way since to reach a couple of amps on 5V for a
disk of 10,000 x the capacity and a minute fraction of the cost.
Amen, brother. 10,000 time the capacity, 1/100 the cost - factor
inflation into it and you have a drop in cost per byte of seven
orders of magnitude. Mind-boggling.
...not to mention the size reduction. The OP refers to a 100-MB drive the size of a washing machine. Several of the 3D-printer motherboards I've bought lately have had 128-MB MicroSD cards bundled with them. That's the capacity of the washer-sized drive and then some, shrunk down to something about the same size as a fingernail...and I think they're making them in at least half-TB sizes nowadays.
Scott Alfter <scott@alfter.diespammersdie.us> wrote:
...not to mention the size reduction. The OP refers to a 100-MB drive the >> size of a washing machine. Several of the 3D-printer motherboards I've
bought lately have had 128-MB MicroSD cards bundled with them. That's the >> capacity of the washer-sized drive and then some, shrunk down to something >> about the same size as a fingernail...and I think they're making them in at >> least half-TB sizes nowadays.
128 GB, surely. And yes, even 1 TB.
On Wed, 14 Jul 2021 23:03:37 +0100 Paul Hardy <p.g.hardy@btinternet.com> wrote:
As an extreme case, I remember a washing machine sized 100MB disk
drive on a VAX minicomputer I managed in the early 1980s, which took
240V three
We have come a long way since to reach a couple of amps on 5V for a
disk of 10,000 x the capacity and a minute fraction of the cost.
Even further since the 1.5MB cartridges I used on an IBM 1130 in
the mid 1970s - they were much less power hungry but took several
minutes to spin up or spin down. The day I corrupted the system disk it
took nearly forty minutes to shut the drives down, boot from a copy,
restore the corrupted disk and put everything back the way it should be
about three minutes before the operator returned.
128 GB, surely. And yes, even 1 TB.
Nope, MB. Big enough for a firmware image (probably its intended use)
and a small handful of gcode files, and that's about it. I'm looking at
one right now, and it says "128MB:"
https://home.alfter.us/s/H4gwc5HSbCZzied
At least there's no danger of it being counterfeit. Who'd bother? :)
On Thu, 15 Jul 2021 09:21:27 +0100, Ahem A Rivet's Shot wrote:
On Wed, 14 Jul 2021 23:03:37 +0100 Paul Hardy <p.g.hardy@btinternet.com>
wrote:
As an extreme case, I remember a washing machine sized 100MB disk
drive on a VAX minicomputer I managed in the early 1980s, which took
240V three
We have come a long way since to reach a couple of amps on 5V for a
disk of 10,000 x the capacity and a minute fraction of the cost.
Even further since the 1.5MB cartridges I used on an IBM 1130 in
the mid 1970s - they were much less power hungry but took several
minutes to spin up or spin down. The day I corrupted the system disk it
took nearly forty minutes to shut the drives down, boot from a copy,
restore the corrupted disk and put everything back the way it should be
about three minutes before the operator returned.
My first computer was an Elliott 503 - Three (IIRC) wardrobe-sized and
shaped grey boxes plus a control desk. It was big because it was built
using discrete transistors. It used 39 bit words in an 8Kword ferrite-
core memory. Each work could hold 2 19 bit instructions. If the 19th bit
was zero the instructions were separate: if it was set, the first
instruction modified the second and ran at 6,7 MHz clock speed. It was designed as a scientific and engineering machine and managed to be a few percent faster at floating point calculation than it was at integer arithmetic. It had another 16Kwords of ferrite core that was used
essentially as a very fast disk: it could be used as workspace for array operations and the Algol compiler, assembler and other support programs
were loaded from it. Apart from that, its only I/O was a fast lineprinter, two paper tape readers and two paper tape punches. I learnt to program in Algol 60 on it during my last year at university.
The Elliott 803s at National Museum Of Computing were binary compatible
with with the 503, but about 70 times slower. However, if you want to see something REALLY slow, visit the NMOC and see the Harwell Dekatron in
action! It uses relay-based logic, Nixie tubes for memory and paper tape
i/o.
But I digress, what I came here to say was that after University, I
joined ICL and learnt PLAN assembler on a 1901 (punched card reader, lineprinter and 4 x 1/2"mag tape drives plus the operator's control teletype). That was quite slow: if the file you wanted was on tape deck
4, but that wasn't online and you realised that after typing GO and
seeing tape 1 start to move, it was possible to get to the tape decks and
put no 4 online while the machine was checking the headers of the tapes
on decks 2 and 3. All ICL 1900s recognised tapes by reading the tape
header rather than by being told which deck your tape was on. Our
operations machine at the time was a 1902 with one of those washing
machine sized disk drives plus lots of tape decks, card readers and a lineprinter. The disk packs were removable, made of a stack of 10 14" ferrite-coated alloy platters, separated by spacers and held together
with a set of (6?) bolts and capable of holding a whole 8 million 6-bit characters.
When off the drive, each disk lived in a clear plastic cover which
included the handle used to lock it onto the drive and with a cover that screwed onto the bottom to keep dust out.
Which brings me to the point of this rigmarole: one day we were doing
some last minute testing, so there were 2 or 3 of us rushing round the machine room and operating the machine to complete testing , when Gary,
the programming manager, realised that the wrong disk for what we were
doing was on the drive, so he rushed over to the disk cabinet, put that
drive into its drawer, grabbed the one we needed and set off at a gallop
for the drive. He'd forgotten one thing: the thread holding the bottom
case on that drive was stripped and fell off in mid-gallop, hitting the
floor with a clatter. He immediately thought "Crap: I've dropped the
bloody disk!" - and let go the handle. Then, realising what he'd done, managed to grab the drive by its handle before it hit the floor, and
managed to put it on the drive before tottering off to recover: unsurprisingly, He wasn't a lot of use for the rest of the day. Just as
well he made the save since we had neither a spare disk nor a backup for
the one he almost smashed.
On Thu, 15 Jul 2021 09:21:27 +0100, Ahem A Rivet's Shot wrote:
On Wed, 14 Jul 2021 23:03:37 +0100 Paul Hardy <p.g.hardy@btinternet.com>
wrote:
As an extreme case, I remember a washing machine sized 100MB disk
drive on a VAX minicomputer I managed in the early 1980s, which took
240V three
What capacity were the large removable multi-platter discs (in a
transparent plastic case with a twist handle) that were used in
mainframe computers of the 1970s? My first sight of a computer was in
the machine hall at ICL's BRA01 (Bracknell) site, when I was on a BASIC course for schoolchildren in 1976. And I saw the operators scurrying
around like ants, removing and replacing discs and tapes.
Even when I started work in 1986, the computers still used open-reel
tapes (as opposed to QIC cartridges). But I think all the discs were
fixed, not with removable platters.
Yeah; when you drop a hard disk you get bits all over the place :-)
What capacity were the large removable multi-platter discs (in a transparent plastic case with a twist handle) that were used in mainframe computers of the 1970s?
I had to adopt a different solution: a SATA HDD and a USB-SATA hub. That allows power to USB-SATA hub and Pi to be applied at the same time, and the Pi boots OK.
In my case, I specifically want a spinning disc because the Pi is used as a PVR, recording TV programmes, so there is a lot of writing and rewriting of data (around 0.5-1.5 GB/hour of recording), and I didn't want to knacker an SSD with frequent writes- the same reason than defragmenters are not recommended for SSDs.
My first computer, a Transam Wren, came with 2 5.25" floppy drives and 16 KB
(yes, kilobytes) of RAM. I decided I could afford the upgrade to 128 ( or
was it 256) KB RAM, but the cost of the upgrade to a 5 MB hard drive was
beyond me. That was in 1981 - I remember driving to Gray's Inn Road in
London to collect it, a few weeks after I'd passed my test.
What capacity were the large removable multi-platter discs (in a transparent >plastic case with a twist handle) that were used in mainframe computers of
"druck" <news@druck.org.uk> wrote in message news:scnh1f$gcp$1@dont-email.me...
On 14/07/2021 09:18, Adam Funk wrote:
Hi,
For a lightweight server based on a Pi 3 or 4, the recommendation was
to use an externally powered USB hard drive (rather than powering it
from the Pi's USB port) for better reliability.
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
I've used an SSD with Pi 3Bs, 3B+s and 4Bs. As long as you use a good
power supply, the Pi can drive these with no issues.
Beware!
A USB HDD needs power which it draws from the USB socket on the Pi. For
an SSD you might be OK but if you use a spinning HDD there is
insufficient power, so the +5V voltage may drop.
Insufficient power from *where*?
The Pi does not *supply* the power - the power supply supplies the power. [...]
Just use a beefier power supply to the Pi in the first place.
On 17-07-2021 07:08, The Natural Philosopher wrote:
Insufficient power from *where*?
The Pi does not *supply* the power - the power supply supplies the power.
[...]
Just use a beefier power supply to the Pi in the first place.
Apparently this is only true for the A+ and Zero (I didn't know this).
On other RPi's from B+ onwards, the current is limited to 1.2 A for all
USB ports together, no matter how beefy the power supply: https://www.raspberrypi.org/documentation/hardware/raspberrypi/power/README.md
On 17/07/2021 12:27 pm, A. Dumas wrote:
Apparently this is only true for the A+ and Zero (I didn't know this).
On other RPi's from B+ onwards, the current is limited to 1.2 A for all
USB ports together, no matter how beefy the power supply:
https://www.raspberrypi.org/documentation/hardware/raspberrypi/power/README.md
Yes, but if your power supply can't provide enough juice to run both the
Pi AND the USB ports, a "bigger" PSU will help.
Even when I started work in 1986, the computers still used open-reelSame here. The only tape I've used at work was 1/2" (7 or 9 track, 10" or
tapes (as opposed to QIC cartridges). But I think all the discs were
fixed, not with removable platters.
12" reels).
At one point I was using 4 GB DAT cartridges for backups at home, but it
was relatively slow, especially compared with any USB-connected HDD. So,
now my backups are all done using USB-connected portable 2.5" drives and using rsync and rsnapshot as the backup software.
Chris Elvidge <chris@mshome.net> wrote:
On 17/07/2021 12:27 pm, A. Dumas wrote:
Apparently this is only true for the A+ and Zero (I didn't know this).
On other RPi's from B+ onwards, the current is limited to 1.2 A for all
USB ports together, no matter how beefy the power supply:
https://www.raspberrypi.org/documentation/hardware/raspberrypi/power/README.md
Yes, but if your power supply can't provide enough juice to run both the
Pi AND the USB ports, a "bigger" PSU will help.
Oh, right, yes. I had assumed that was a step already taken. At least it
is
for the "official power supply" which I always used from the Pi 3 onwards after the slightly cheaper ones I used for the Pi 2 gave me trouble on the
Pi 3.
On Fri, 16 Jul 2021 21:46:59 +0100, "NY" <me@privacy.invalid> declaimed
the
following:
(yes, kilobytes) of RAM. I decided I could afford the upgrade to 128 ( or >>was it 256) KB RAM, but the cost of the upgrade to a 5 MB hard drive was
1981... 256kB... ???
Insufficient power from *where*?
The Pi does not *supply* the power - the power supply supplies the power.
<Snip irrelevant bollocks about powered hubs.>
Just use a beefier power supply to the Pi in the first place.
Just use a beefier power supply to the Pi in the first place.
As an aside, I spent a lot of time in a team at ICL which ported what
was effectively SAMBA onto ICL servers and network protocols. We sold it
to various customers. Now that functionality (minus the domain-control
stuff *) is available for free as a downloadable package on any Linux.
(*) Domain and permission stuff bored me: I'm more turned on by making
things possible, rather than by making things impossible for
unauthorised people. Security is essential - but boring ;-)
On 17-07-2021 07:08, The Natural Philosopher wrote:
Insufficient power from *where*?
The Pi does not *supply* the power - the power supply supplies the power.
[...]
Just use a beefier power supply to the Pi in the first place.
Apparently this is only true for the A+ and Zero (I didn't know this).
On other RPi's from B+ onwards, the current is limited to 1.2 A for all
USB ports together, no matter how beefy the power supply: https://www.raspberrypi.org/documentation/hardware/raspberrypi/power/README.md
"The Natural Philosopher" <tnp@invalid.invalid> wrote in message news:sctokq$md2$6@dont-email.me...
Insufficient power from *where*?
The Pi does not *supply* the power - the power supply supplies the power.
<Snip irrelevant bollocks about powered hubs.>
Just use a beefier power supply to the Pi in the first place.
My understanding was that the Pi does some voltage conversion or stabilisation, and that simply adding a 5V PSU that is capable of
supplying more current/power to the Pi doesn't allow more power-hungry devices to be connected to the Pi's USB ports.
Certainly I saw the CPU temperature (as reported by the taskbar widget)
rise when I plugged in an HDD, which suggests that the input power rail
from the PSU is not electrically connected to the output power rail of
the USB port, but that circuitry on the Pi motherboard is place "in
between".
On Sat, 17 Jul 2021 19:15:44 +0100, NY wrote:
As an aside, I spent a lot of time in a team at ICL which ported whatOn which ICL hardware and OS?
was effectively SAMBA onto ICL servers and network protocols. We sold it
to various customers. Now that functionality (minus the domain-control
stuff *) is available for free as a downloadable package on any Linux.
I was half right: https://www.old-computers.com/museum/computer.asp?st=1&c=257 says "RAM 64 kb (up to 256 kb)" so I was out by a factor of 8 - if that information is correct and they really do mean bits rather that bytes.
Why they don't bypass its power stuff and feed power straight to the
USBs, only some pointy headed Pi designer knows.
"Martin Gregorie" <martin@mydomain.invalid> wrote in message news:scvdat$i3t$1@dont-email.me...
On Sat, 17 Jul 2021 19:15:44 +0100, NY wrote:
As an aside, I spent a lot of time in a team at ICL which ported whatOn which ICL hardware and OS?
was effectively SAMBA onto ICL servers and network protocols. We sold
it to various customers. Now that functionality (minus the
domain-control stuff *) is available for free as a downloadable
package on any Linux.
DRS3000 (Intel) and DRS6000 (SPARC) running Unix. This was in the 1990s.
The source code that we bought was written for Intel, and we had to do a *lot* of #ifdefs for SPARC to reverse the byte ordering of multi-byte integers between the format in the packets received and the native
format of the CPU.
True enough, but a well-designed security system should not interfere
with normal activity by an authorised user. UNIX/Linux is less annoying
than other OSen I've used, but it limited by being a two-level system
('root' + other users).
On Sun, 18 Jul 2021 08:28:38 +0100, The Natural Philosopher wrote:
Why they don't bypass its power stuff and feed power straight to theWouldn't that require much wider power rails? Maybe there simply wasn't enough space on the PCB to accommodate that without making the PCB bigger?
USBs, only some pointy headed Pi designer knows.
On 17-07-2021 20:27, NY wrote:
I was half right:
https://www.old-computers.com/museum/computer.asp?st=1&c=257 says
"RAM 64 kb (up to 256 kb)" so I was out by a factor of 8 - if
that information is correct and they really do mean bits rather that
bytes.
Would be unusual to mean bit in that context. I can believe a 1984 Z80
based computer to have 64 KiB! They also write "12 Kg" so I don't trust
their capitalisation skills.
Why they don't bypass its power stuff and feed power straight to the
USBs, only some pointy headed Pi designer knows.
I am frankly flabbergasted that such a crap piece of design was
incorporated
On 18/07/2021 12:06, Martin Gregorie wrote:
On Sun, 18 Jul 2021 08:28:38 +0100, The Natural Philosopher wrote:These are all multilayer boards
Why they don't bypass its power stuff and feed power straight to theWouldn't that require much wider power rails? Maybe there simply wasn't
USBs, only some pointy headed Pi designer knows.
enough space on the PCB to accommodate that without making the PCB
bigger?
On 17-07-2021 20:27, NY wrote:
I was half right: https://www.old-computers.com/museum/computer.asp?st=1&c=257 says "RAM 64 kb (up to 256 kb)" so I was out by a factor of 8 - if that
information is correct and they really do mean bits rather that bytes.
Would be unusual to mean bit in that context. I can believe a 1984 Z80
based computer to have 64 KiB! They also write "12 Kg" so I don't trust
their capitalisation skills.
Why they don't bypass its power stuff and feed power straight to the
USBs, only some pointy headed Pi designer knows.
On Sun, 18 Jul 2021 14:12:14 +0100, The Natural Philosopher wrote:
On 18/07/2021 12:06, Martin Gregorie wrote:
On Sun, 18 Jul 2021 08:28:38 +0100, The Natural Philosopher wrote:These are all multilayer boards
Why they don't bypass its power stuff and feed power straight toWouldn't that require much wider power rails? Maybe there simply
the USBs, only some pointy headed Pi designer knows.
wasn't enough space on the PCB to accommodate that without making
the PCB bigger?
Understood, but are the ground and positive rails duplicated on more
than one layer? Or are they significantly wider than signal lines?
Its difficult to tell from visual inspection.
On Sun, 18 Jul 2021 14:12:14 +0100, The Natural Philosopher wrote:
On 18/07/2021 12:06, Martin Gregorie wrote:
On Sun, 18 Jul 2021 08:28:38 +0100, The Natural Philosopher wrote:These are all multilayer boards
Why they don't bypass its power stuff and feed power straight to theWouldn't that require much wider power rails? Maybe there simply wasn't
USBs, only some pointy headed Pi designer knows.
enough space on the PCB to accommodate that without making the PCB
bigger?
Understood, but are the ground and positive rails duplicated on more than
one layer? Or are they significantly wider than signal lines? Its
difficult to tell from visual inspection.
On 18/07/2021 15:51, Martin Gregorie wrote:
On Sun, 18 Jul 2021 14:12:14 +0100, The Natural Philosopher wrote:The tendency used to be to have ground on top solid as a shield, and
On 18/07/2021 12:06, Martin Gregorie wrote:
On Sun, 18 Jul 2021 08:28:38 +0100, The Natural Philosopher wrote:These are all multilayer boards
Why they don't bypass its power stuff and feed power straight to the >>>>> USBs, only some pointy headed Pi designer knows.Wouldn't that require much wider power rails? Maybe there simply
wasn't enough space on the PCB to accommodate that without making the
PCB bigger?
Understood, but are the ground and positive rails duplicated on more
than one layer? Or are they significantly wider than signal lines? Its
difficult to tell from visual inspection.
another layer was the power supply lines.
But I never designed a surface mount board :-)
signal wiring could then go north south in one layer and east west on another!
Hi,--- SoupGate-Win32 v1.05
For a lightweight server based on a Pi 3 or 4, the recommendation was
to use an externally powered USB hard drive (rather than powering it
from the Pi's USB port) for better reliability.
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
Thanks.
Maybe I've been lucky, YMMV, etc, but I've had an RPi 3B+ with a WD
Elements portable hard drive (no separate power supply) working for
several years without any problems that I've noticed.
The tendency used to be to have ground on top solid as a shield, and
another layer was the power supply lines.
But I never designed a surface mount board :-)
signal wiring could then go north south in one layer and east west on another!
On 14/07/2021 09:18, Adam Funk wrote:
Hi,
For a lightweight server based on a Pi 3 or 4, the recommendation was
to use an externally powered USB hard drive (rather than powering it
from the Pi's USB port) for better reliability.
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
Thanks.
If it's mostly read access, and 256 GB suffices, you might consider a 256 GB USB stick, as there's not that expensive.
https://www.amazon.co.uk/SanDisk-Ultra-USB-Flash-Drive/dp/B00YFI1A66
I see 1 TB at a similar price, but I would buy a brand I trust!
"druck" <news@druck.org.uk> wrote in message news:scnh1f$gcp$1@dont-email.me...
On 14/07/2021 09:18, Adam Funk wrote:
Hi,
For a lightweight server based on a Pi 3 or 4, the recommendation was
to use an externally powered USB hard drive (rather than powering it
from the Pi's USB port) for better reliability.
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
I've used an SSD with Pi 3Bs, 3B+s and 4Bs. As long as you use a good
power supply, the Pi can drive these with no issues.
Beware!
A USB HDD needs power which it draws from the USB socket on the Pi. For an SSD you might be OK but if you use a spinning HDD there is insufficient power, so the +5V voltage may drop.
The solution to this is to use a powered USB hub.
I did this for my Pi3 and
everything worked perfectly. But for the Pi4, the Pi would not boot if the power to the USB hub and to the Pi were applied at the same time - for example after a power cut. Ass soon as I unplugged the hub from the PI, it booted immediately, as if it had been hanging indefinitely. It's to do with the hub supplying power upstream to the Pi as well as downstream to the HDD, which for some reason the Pi3 is happy with but the Pi4 is not. I tried a different make of hub and also a special USB cable between Pi and hub in which I had cut the +5V wire, but to not avail.
I had to adopt a different solution: a SATA HDD and a USB-SATA hub. That allows power to USB-SATA hub and Pi to be applied at the same time, and the Pi boots OK.
In my case, I specifically want a spinning disc because the Pi is used as a PVR, recording TV programmes, so there is a lot of writing and rewriting of data (around 0.5-1.5 GB/hour of recording), and I didn't want to knacker an SSD with frequent writes - the same reason than defragmenters are not recommended for SSDs.
I thought about that but the main purpose is off-site backups by scp
so there will be a lot of writing.
On 2021-07-16, David Taylor wrote:
On 14/07/2021 09:18, Adam Funk wrote:
Hi,If it's mostly read access, and 256 GB suffices, you might consider a
For a lightweight server based on a Pi 3 or 4, the recommendation was
to use an externally powered USB hard drive (rather than powering it
from the Pi's USB port) for better reliability.
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like
a Samsung T5 or T7 500 GB USB SSD.
Thanks.
256 GB USB stick, as there's not that expensive.
https://www.amazon.co.uk/SanDisk-Ultra-USB-Flash-Drive/dp/B00YFI1A66
I see 1 TB at a similar price, but I would buy a brand I trust!
I thought about that but the main purpose is off-site backups by scp so
there will be a lot of writing.
On 20/07/2021 11:09, Adam Funk wrote:
I thought about that but the main purpose is off-site backups by scp
so there will be a lot of writing.
Agreed. So an interesting decision between HDD and SSD! Some SSDs do
have a write-limit specified, although my first reaction would be if
it's off-site and over the network perhaps SSD might be the better
choice.
Are you allowing incremental backups, or full backup each time?
"rsync -auv /my/dir server:"
On 21/07/2021 08:47, A. Dumas wrote:
In this case my choice would be a HDD because the latency andThe latency of a network filing system is still orders of magnitude
throughput are almost certainly limited by the network, not the drive,
and a HDD is still quite a bit cheaper than an SSD.
better than a hard disc, and with true gigabit Ethernet on the Pi 4, it
just about matches the throughput of a USB3 attached hard disc. Plus you don't have to wait for the disc to spin up on your first access.
In this case my choice would be a HDD because the latency and throughputThe latency of a network filing system is still orders of magnitude
are almost certainly limited by the network, not the drive, and a HDD is still quite a bit cheaper than an SSD.
Or maybe you could go for an
enterprise grade storage HDD for the same money
On Tue, 20 Jul 2021 11:09:42 +0100, Adam Funk wrote:
On 2021-07-16, David Taylor wrote:
On 14/07/2021 09:18, Adam Funk wrote:
Hi,If it's mostly read access, and 256 GB suffices, you might consider a
For a lightweight server based on a Pi 3 or 4, the recommendation was
to use an externally powered USB hard drive (rather than powering it
from the Pi's USB port) for better reliability.
Now that you can get external USB SSD units (which draw less power
than HDDs) is it OK to use one for this? I had in mind something like >>>> a Samsung T5 or T7 500 GB USB SSD.
Thanks.
256 GB USB stick, as there's not that expensive.
https://www.amazon.co.uk/SanDisk-Ultra-USB-Flash-Drive/dp/B00YFI1A66
I see 1 TB at a similar price, but I would buy a brand I trust!
I thought about that but the main purpose is off-site backups by scp so
there will be a lot of writing.
Have you thought about doing anything to minimise backup write/delete volumes, i.e. using rsync or rsnapshot to do the backups?
Both back up only new or changed files and remove erased files from the backup media. The difference is that rsync maintains a backup copy of the files on the disk as it stands while rsnapshot keeps track of the disk as
it was over a period of days and weeks, using symlinks so that unchanging files only have a single copy on the backup disk.
The speed is nice: when I made compressed backups using tar the nightly backup took 3-4 hours: switching to rsnapshot has brought this down to 9 minutes a night and I can now look back across 4 weeks worth of backups compared with 13 days for zipped tar files - on the same computer and
backup volume.
On 21/07/2021 08:47, A. Dumas wrote:
In this case my choice would be a HDD because the latency andThe latency of a network filing system is still orders of magnitude
throughput are almost certainly limited by the network, not the drive,
and a HDD is still quite a bit cheaper than an SSD.
better than a hard disc, and with true gigabit Ethernet on the Pi 4, it
just about matches the throughput of a USB3 attached hard disc. Plus you don't have to wait for the disc to spin up on your first access.
On 21/07/2021 21:21, druck wrote:
On 21/07/2021 08:47, A. Dumas wrote:
In this case my choice would be a HDD because the latency and throughput >>> are almost certainly limited by the network, not the drive, and a HDD is >>> still quite a bit cheaper than an SSD.The latency of a network filing system is still orders of magnitude
better than a hard disc, and with true gigabit Ethernet on the Pi 4, it
just about matches the throughput of a USB3 attached hard disc. Plus you
don't have to wait for the disc to spin up on your first access.
A quick look at my rpi4 USB SSD says network speeds are barely just over
half local speeds, Network read speed is 118MB/s, local buffered is 224
MB/s (from sudo hdparm -Tt /dev/sdb)
I suspect an SSD is more durable than a HDD too (time will tell). HDDs are cheaper and may be less susceptible to total catastrophic data loss.
An RPI4 USB SSD combination is a workable NAS solution.
Not sure buffered reads are actual real, as opposed to only using a
small buffer and hence almost real disk reads.
Is the file in the cache, i.e pick a file you know isn't. My Pi is using >about 3GB of its RAM as a file cache.
"Pancho" <Pancho.Dontmaileme@outlook.com> wrote in message news:sdc5da$3he$1@dont-email.me...
On 21/07/2021 21:21, druck wrote:
On 21/07/2021 08:47, A. Dumas wrote:
In this case my choice would be a HDD because the latency andThe latency of a network filing system is still orders of magnitude
throughput are almost certainly limited by the network, not the
drive, and a HDD is still quite a bit cheaper than an SSD.
better than a hard disc, and with true gigabit Ethernet on the Pi 4,
it just about matches the throughput of a USB3 attached hard disc.
Plus you don't have to wait for the disc to spin up on your first
access.
A quick look at my rpi4 USB SSD says network speeds are barely just
over half local speeds, Network read speed is 118MB/s, local buffered
is 224 MB/s (from sudo hdparm -Tt /dev/sdb)
I suspect an SSD is more durable than a HDD too (time will tell). HDDs
are cheaper and may be less susceptible to total catastrophic data loss.
An RPI4 USB SSD combination is a workable NAS solution.
Is it the case that "an SSD is more durable than a HDD", given the
finite lifetime of the NAND gates to repeated changes of state? AFAIK
the magnetism of an HDD does not have a finite number of changes after
which the error rate starts to increase, although it *does* have moving
parts (head arm and spinning platters). I suppose wear-levelling
firmware in the SSD tends to mitigate the finite-write limit a bit.
Would you recommend a USB SSD for something like a PVR where very large
files are frequently being written, erased and new files written. Is the finite-write thing less of an issue than it used to be?
I've just tried a copy of a large file between Windows and Pi over SMB
share and gigabit Ethernet.
hdparm gives:
cached reads 750.02 MB/sec
buffered reads 75.54 MB/sec
copying Windows to Pi (writing to Pi) 1,389,566,656 in 52.9 seconds =
26.3 MB/sec
copying Pi to Windows (reading from Pi) 1,389,566,656 in 13.1 seconds =
106.1 MB/sec
Both transfers initiated from the Windows computer. I'm not sure how to
make a Pi connect to a Windows SMB share - I always get permission
problems to establish the initial SMB session, before actual file
read/write begins.
The writing is roughly 1/4 of the theoretical LAN rate; the reading is
pretty much 100% gigabit speed, as shown by the Windows Task Manager | Networking graph.
Hold on a mo... my "copying Pi to Windows (reading from Pi)" is faster
than hdparm's buffered read figure which is the one which tests real
disk reads as opposed to cached ones of CPU, RAM and HDD cache but not physical read. Can anyone explain this?
I'm just a guy on the internet, but My 500GB Samsung EVO 850 has an
endurance 150 TBW. Assuming 10 year life span that is about 40 GB write
a day.
After 5+ years I'm at GB Written: 41,704.488. So not even a third used up.
A comparable drive today is £43 Kingston A400 480GB. If I had a high
Is it the case that "an SSD is more durable than a HDD", given the
finite lifetime of the NAND gates to repeated changes of state? AFAIK
the magnetism of an HDD does not have a finite number of changes after
which the error rate starts to increase, although it *does* have moving
parts (head arm and spinning platters). I suppose wear-levelling
firmware in the SSD tends to mitigate the finite-write limit a bit.
files are frequently being written, erased and new files written. Is the finite-write thing less of an issue than it used to be?
Would you recommend a USB SSD for something like a PVR where very large
files are frequently being written, erased and new files written. Is the finite-write thing less of an issue than it used to be?
Is it the case that "an SSD is more durable than a HDD", given the
finite lifetime of the NAND gates to repeated changes of state? AFAIK
the magnetism of an HDD does not have a finite number of changes after
which the error rate starts to increase, although it *does* have
moving parts (head arm and spinning platters). I suppose
wear-levelling firmware in the SSD tends to mitigate the finite-write
limit a bit.
On 21/07/2021 21:21, druck wrote:
On 21/07/2021 08:47, A. Dumas wrote:
In this case my choice would be a HDD because the latency andThe latency of a network filing system is still orders of magnitude
throughput are almost certainly limited by the network, not the
drive, and a HDD is still quite a bit cheaper than an SSD.
better than a hard disc, and with true gigabit Ethernet on the Pi 4,
it just about matches the throughput of a USB3 attached hard disc.
Plus you don't have to wait for the disc to spin up on your first access.
A quick look at my rpi4 USB SSD says network speeds are barely just over
half local speeds, Network read speed is 118MB/s, local buffered is 224
MB/s (from sudo hdparm -Tt /dev/sdb)
I suspect an SSD is more durable than a HDD too (time will tell). HDDs
are cheaper and may be less susceptible to total catastrophic data loss.
An RPI4 USB SSD combination is a workable NAS solution.
interrogating my units with smartctl reveals that their projected life exceeds my average hard drive life: In short SSDs are now better than
HDDs in every respect except price
"NY" <me@privacy.invalid> writes:
Is it the case that "an SSD is more durable than a HDD", given the
finite lifetime of the NAND gates to repeated changes of state? AFAIK
the magnetism of an HDD does not have a finite number of changes after
which the error rate starts to increase, although it *does* have
moving parts (head arm and spinning platters). I suppose
wear-levelling firmware in the SSD tends to mitigate the finite-write
limit a bit.
I’ve had one SSD fail in the last 10 years (and that was an OCZ), I’ve lost count of how many HDDs I’ve had fail in the same interval.
Personally I go for 'refurbished'[1] ex data centre 3.5" SAS drives
for bulk data. They're dirt cheap and tend to have nearly idled for three >years before being replaced because of age so for all practical purposes >they're nearly new and plenty fast enough until the network goes to 10gig, >not soon at today's prices!
In article <20210723110634.aeeb1ec482baef80bdcd65f9@eircom.net>,drives
Ahem A Rivet's Shot <steveo@eircom.net> wrote:
Personally I go for 'refurbished'[1] ex data centre 3.5" SAS
for bulk data. They're dirt cheap and tend to have nearly idled for
three years before being replaced because of age so for all practical >>purposes they're nearly new and plenty fast enough until the network
goes to 10gig,
not soon at today's prices!
How do you go about connecting them? AFAIK, you can't hang them off a
SATA port and there are no USB-to-SAS adapters
On Fri, 23 Jul 2021 19:55:10 +0000, Scott Alfter wrote:
In article <20210723110634.aeeb1ec482baef80bdcd65f9@eircom.net>,drives
Ahem A Rivet's Shot <steveo@eircom.net> wrote:
Personally I go for 'refurbished'[1] ex data centre 3.5" SAS
Yes there are: they're all over eBak and Amazon like a rash. eBuyer sells them too.for bulk data. They're dirt cheap and tend to have nearly idled for
three years before being replaced because of age so for all practical
purposes they're nearly new and plenty fast enough until the network
goes to 10gig,
not soon at today's prices!
How do you go about connecting them? AFAIK, you can't hang them off a
SATA port and there are no USB-to-SAS adapters
--
Martin | martin at
Gregorie | gregorie dot org
Martin Gregorie wrote on 7/23/21 10:42 PM:
On Fri, 23 Jul 2021 19:55:10 +0000, Scott Alfter wrote:you're probably talking SATA, a SAS Adapter sets you back around 500 euros.....
In article <20210723110634.aeeb1ec482baef80bdcd65f9@eircom.net>,drives
Ahem A Rivet's Shot <steveo@eircom.net> wrote:
Personally I go for 'refurbished'[1] ex data centre 3.5" SAS
Yes there are: they're all over eBak and Amazon like a rash. eBuyerfor bulk data. They're dirt cheap and tend to have nearly idled for
three years before being replaced because of age so for all practical
purposes they're nearly new and plenty fast enough until the network
goes to 10gig,
not soon at today's prices!
How do you go about connecting them? AFAIK, you can't hang them off a
SATA port and there are no USB-to-SAS adapters
sells them too.
--
Martin | martin at Gregorie | gregorie dot org
On Sat, 24 Jul 2021 09:41:22 +0200, Ralph Spitzner wrote:
Martin Gregorie wrote on 7/23/21 10:42 PM:
On Fri, 23 Jul 2021 19:55:10 +0000, Scott Alfter wrote:you're probably talking SATA, a SAS Adapter sets you back around 500
In article <20210723110634.aeeb1ec482baef80bdcd65f9@eircom.net>,drives
Ahem A Rivet's Shot <steveo@eircom.net> wrote:
Personally I go for 'refurbished'[1] ex data centre 3.5" SAS
Yes there are: they're all over eBak and Amazon like a rash. eBuyerfor bulk data. They're dirt cheap and tend to have nearly idled for
three years before being replaced because of age so for all practical >>>>> purposes they're nearly new and plenty fast enough until the network >>>>> goes to 10gig,
not soon at today's prices!
How do you go about connecting them? AFAIK, you can't hang them off a >>>> SATA port and there are no USB-to-SAS adapters
sells them too.
--
Martin | martin at Gregorie | gregorie dot org
euros.....
The prices I saw at Amazon and eBay seem to range from about GBP 8 to GBP
25 and a little more at Ebuyer, so a lot less than 500 euros. These are
all USB3->SATA cables for 2.5"/3.4" disks.
On Sat, 24 Jul 2021 13:38:45 -0000 (UTC)
A. Dumas <alexandre@dumas.fr.invalid> wrote:
Not quite, you can connect SATA drives to SAS controllers but not
the other way round.
Not sure what use sas->sata
pin adapters are if they don't translate the protocol.
Attaching SATA drives to SAS controllers.
Martin Gregorie <martin@mydomain.invalid> wrote:
On Sat, 24 Jul 2021 09:41:22 +0200, Ralph Spitzner wrote:
The prices I saw at Amazon and eBay seem to range from about GBP 8 to
GBP 25 and a little more at Ebuyer, so a lot less than 500 euros. These
are all USB3->SATA cables for 2.5"/3.4" disks.
No, *SAS* = serial attached scsi, which can be made pin compatible to SATA but they are completely different protocols.
Not sure what use sas->sata
pin adapters are if they don't translate the protocol.
Sata->usb is dirt
cheap, but look at this typical sas->usb solution: https://www.aliexpress.com/i/32982096906.html for $599.
On Sat, 24 Jul 2021 09:41:22 +0200, Ralph Spitzner wrote:
Martin Gregorie wrote on 7/23/21 10:42 PM:The prices I saw at Amazon and eBay seem to range from about GBP 8 to GBP
On Fri, 23 Jul 2021 19:55:10 +0000, Scott Alfter wrote:you're probably talking SATA, a SAS Adapter sets you back around 500
In article <20210723110634.aeeb1ec482baef80bdcd65f9@eircom.net>,drives
Ahem A Rivet's Shot <steveo@eircom.net> wrote:
Personally I go for 'refurbished'[1] ex data centre 3.5" SAS
Yes there are: they're all over eBak and Amazon like a rash. eBuyerfor bulk data. They're dirt cheap and tend to have nearly idled for
three years before being replaced because of age so for all practical >>>>> purposes they're nearly new and plenty fast enough until the network >>>>> goes to 10gig,
not soon at today's prices!
How do you go about connecting them? AFAIK, you can't hang them off a >>>> SATA port and there are no USB-to-SAS adapters
sells them too.
--
Martin | martin at Gregorie | gregorie dot org
euros.....
25 and a little more at Ebuyer, so a lot less than 500 euros. These are
all USB3->SATA cables for 2.5"/3.4" disks.
For a bit more (though still not nearly 500 euros) you can get a cable
that connects 2-3 disks or a unit thats a USB3-connected plastic disk enclosure - think of a single disk 'dock' but with the disk mounted flat rather than on end.
On Sat, 24 Jul 2021 09:41:22 +0200, Ralph Spitzner wrote:
Martin Gregorie wrote on 7/23/21 10:42 PM:The prices I saw at Amazon and eBay seem to range from about GBP 8 to GBP
On Fri, 23 Jul 2021 19:55:10 +0000, Scott Alfter wrote:you're probably talking SATA, a SAS Adapter sets you back around 500
In article <20210723110634.aeeb1ec482baef80bdcd65f9@eircom.net>,drives
Ahem A Rivet's Shot <steveo@eircom.net> wrote:
Personally I go for 'refurbished'[1] ex data centre 3.5" SAS
Yes there are: they're all over eBak and Amazon like a rash. eBuyerfor bulk data. They're dirt cheap and tend to have nearly idled for
three years before being replaced because of age so for all practical >>>>> purposes they're nearly new and plenty fast enough until the network >>>>> goes to 10gig,
not soon at today's prices!
How do you go about connecting them? AFAIK, you can't hang them off a >>>> SATA port and there are no USB-to-SAS adapters
sells them too.
--
Martin | martin at Gregorie | gregorie dot org
euros.....
25 and a little more at Ebuyer, so a lot less than 500 euros. These are
all USB3->SATA cables for 2.5"/3.4" disks.
SAS != SATA. The OP mentioned using ex-datacenter SAS drives for bulk
data storage. Unless you're buying cheap used servers to house them,
you're going to have a hard time making use of them.
| Sysop: | Keyop |
|---|---|
| Location: | Huddersfield, West Yorkshire, UK |
| Users: | 422 |
| Nodes: | 16 (0 / 16) |
| Uptime: | 179:47:33 |
| Calls: | 8,942 |
| Calls today: | 9 |
| Files: | 13,352 |
| Messages: | 5,990,857 |