Dear all,

I am running Ubuntu 16.04 LTS 64 bits on a DEll laptop with the specs below: RAM: 4GB
Proc: Intel DUo core 1.8Ghz
Disk: 160 Gb Plain HD

Since One year now on, I have been experienced slow downs with long disk reads, while front running no other software than Chromium. I am not running any significant server process, using my PC as a home terminal.

I have just realised that the HD is partionned with a swap area size 4.1Gb that I cannot activate:

Error activating swap: Command-line `swapon "/dev/sda7"' exited with non-zero exit status 255: swapon: /dev/sda7: swapon failed: Device or resource busy
(udisks-error-quark, 0)

But I remember having activated long ago when I installed the OS.

How to diagnosise what is going on and possibly improve the performance of my PC without any material upgrade? (It would be impossible to add up RAM since all slots are occupied and no larger capacity RAM modules is available)

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Wednesday, 5 June 2019 14:02:22 UTC+2, Artis Sideley wrote:

Dear all,

I am running Ubuntu 16.04 LTS 64 bits on a DEll laptop with the specs below: RAM: 4GB
Proc: Intel DUo core 1.8Ghz
Disk: 160 Gb Plain HD

Since One year now on, I have been experienced slow downs with long disk reads, while front running no other software than Chromium. I am not running any significant server process, using my PC as a home terminal.

I have just realised that the HD is partionned with a swap area size 4.1Gb that I cannot activate:

Error activating swap: Command-line `swapon "/dev/sda7"' exited with non-zero exit status 255: swapon: /dev/sda7: swapon failed: Device or resource busy
(udisks-error-quark, 0)

But I remember having activated long ago when I installed the OS.

How to diagnosise what is going on and possibly improve the performance of my PC without any material upgrade? (It would be impossible to add up RAM since all slots are occupied and no larger capacity RAM modules is available)

Actually, using the "Disks" application, the overal disk mapping shows all partitions on the HD drive including a 4.1Gb partition used as swap but inactivated, unlike others. But below, there is this line showing the swap partition in question as a drive,
and according to this view, the swap drive is active...
What manual command to make sure of what going on?

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Wednesday, 5 June 2019 14:02:22 UTC+2, Artis Sideley wrote:

Dear all,

I am running Ubuntu 16.04 LTS 64 bits on a DEll laptop with the specs below: RAM: 4GB
Proc: Intel DUo core 1.8Ghz
Disk: 160 Gb Plain HD

Since One year now on, I have been experienced slow downs with long disk reads, while front running no other software than Chromium. I am not running any significant server process, using my PC as a home terminal.

I have just realised that the HD is partionned with a swap area size 4.1Gb that I cannot activate:

Error activating swap: Command-line `swapon "/dev/sda7"' exited with non-zero exit status 255: swapon: /dev/sda7: swapon failed: Device or resource busy
(udisks-error-quark, 0)

But I remember having activated long ago when I installed the OS.

How to diagnosise what is going on and possibly improve the performance of my PC without any material upgrade? (It would be impossible to add up RAM since all slots are occupied and no larger capacity RAM modules is available)

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

Il giorno Wed 05 Jun 2019 02:02:20p, *Artis Sideley* ha inviato su comp.os.linux.setup il messaggio news:0d2a713a-4cd5-4bdf-9308- 5a74f15c91b5@googlegroups.com. Vediamo cosa ha scritto:

possibly improve the performance of my PC without any material upgrade?

replace the HDD with a SSD, I think this is the cheapest solution (a 250Gb
disk is available on amazon for less than 30$)

I used a similar s.o. (Mint 16) with just 2Gb RAM and performance has
always been more than satisfying

--
/-\ /\/\ /\/\ /-\ /\/\ /\/\ /-\ T /-\
-=- -=- -=- -=- -=- -=- -=- -=- - -=-

http://www.bb2002.it :) <<<<<

........... [ al lavoro ] ...........

--- SoupGate-Win32 v1.05
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On 2019-06-05, Bobbie Sellers <bliss@mouse-potato.com> wrote:

On 6/5/19 5:02 AM, Artis Sideley wrote:

Dear all,

I am running Ubuntu 16.04 LTS 64 bits on a DEll laptop with the specs below:
RAM: 4GB
Proc: Intel DUo core 1.8Ghz
Disk: 160 Gb Plain HD

Since One year now on, I have been experienced slow downs with long disk reads, while front running no other software than Chromium. I am not running any significant server process, using my PC as a home terminal.

a) Your disk is failing, and it is rereading many times certain sectors
of the disk
b) your machine is swapping.

I have just realised that the HD is partionned with a swap area size 4.1Gb that I cannot activate:

You do not have to do that any longer. You just create it when you install the system and you are in business.

It still has to be mounted as a swap partition.

Error activating swap: Command-line `swapon "/dev/sda7"' exited with non-zero exit status 255: swapon: /dev/sda7: swapon failed: Device or resource busy
(udisks-error-quark, 0)

Is /dev/sda7 your swap partition? Or has something in /etc/fstab gotten confused.

But I remember having activated long ago when I installed the OS.

How to diagnosise what is going on and possibly improve the performance of my PC without any material upgrade? (It would be impossible to add up RAM since all slots are occupied and no larger capacity RAM modules is available)

Check (eg using fstab or gparted) that /dev/sda7 really is the partition
you want to use as a swap partition, and than the partition table
regards that as a swap type partition.
Eg, fdisk -l /dev/sda
and see if /dev/sda7 is a swap partition.

Try running the command it suggests as root on a console to see what
error messages it gives you.
swapon "/dev/sda7"

Do df to see if /dev/sda7 is mounted somewhere.

Well I just put two 8 GB SODIMMs in this older Dell Latitude E6540 and it did not help the slowdown due to newest kernel changes very much.
Have you searched on the Internet (using DuckDuckGo preferably)
with your model number and maximum ram? Have you downloaded the user manual/service manual?
The E6540 got to me with two 4 GB SODIMMs, but I run a lot of stuff
on an average day and 8 GB always felt crowded.

One of the other people replying to your post suggested
an Solid State Hard drive. On my E6520 the delay was much reduced
when I was using the Dual-Boot 120 GB hard drive.

bliss

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 6/5/19 5:02 AM, Artis Sideley wrote:

Dear all,

I am running Ubuntu 16.04 LTS 64 bits on a DEll laptop with the specs below: RAM: 4GB
Proc: Intel DUo core 1.8Ghz
Disk: 160 Gb Plain HD

Since One year now on, I have been experienced slow downs with long disk reads, while front running no other software than Chromium. I am not running any significant server process, using my PC as a home terminal.

I have just realised that the HD is partionned with a swap area size 4.1Gb that I cannot activate:

You do not have to do that any longer. You just create it when you install the system and you are in business.

Error activating swap: Command-line `swapon "/dev/sda7"' exited with non-zero exit status 255: swapon: /dev/sda7: swapon failed: Device or resource busy
(udisks-error-quark, 0)

But I remember having activated long ago when I installed the OS.

How to diagnosise what is going on and possibly improve the performance of my PC without any material upgrade? (It would be impossible to add up RAM since all slots are occupied and no larger capacity RAM modules is available)

Well I just put two 8 GB SODIMMs in this older Dell Latitude E6540 and it did not help the slowdown due to newest kernel changes very much.
Have you searched on the Internet (using DuckDuckGo preferably)
with your model number and maximum ram? Have you downloaded the user manual/service manual?
The E6540 got to me with two 4 GB SODIMMs, but I run a lot of stuff
on an average day and 8 GB always felt crowded.

One of the other people replying to your post suggested
an Solid State Hard drive. On my E6520 the delay was much reduced
when I was using the Dual-Boot 120 GB hard drive.

bliss

--
bliss dash SF 4 ever at dslextreme dot com

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

Artis Sideley <sideley@yahoo.com> writes:

I am running Ubuntu 16.04 LTS 64 bits on a DEll laptop with the specs below: RAM: 4GB
Proc: Intel DUo core 1.8Ghz
Disk: 160 Gb Plain HD

Since One year now on, I have been experienced slow downs with long
disk reads, while front running no other software than Chromium. I am
not running any significant server process, using my PC as a home
terminal.

I have just realised that the HD is partionned with a swap area size
4.1Gb that I cannot activate:

Error activating swap: Command-line `swapon "/dev/sda7"' exited with
non-zero exit status 255: swapon: /dev/sda7: swapon failed: Device or resource busy
(udisks-error-quark, 0)

But I remember having activated long ago when I installed the OS.

How to diagnosise what is going on and possibly improve the
performance of my PC without any material upgrade? (It would be
impossible to add up RAM since all slots are occupied and no larger
capacity RAM modules is available)

Measure before guessing what’s going on. Use iotop and top to see what
is using IO, CPU and memory resources. top will tell you have much swap
you actually have.

--
https://www.greenend.org.uk/rjk/

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

Thanks to all of you.

The error message is copied pasted from the contextual pop up pane.
Command fdisk displays /dev/sda7 as "Linux swap / Solaris", but unlike with application Disks, the indicated size is 3.8Gb.
Command df does not show any line mentionning /dev/sda7.
Command top regularly shows Chromium as the biggest memory user.
I searched ebay RAM module for my Vostro 1510 and found only one offer selling 4Gb Dimm module at the astronomic price of US$100. Other offers only propose 1 or 2 Gb modules.
The S.M.A.R.T test run on my HD shows no worrying parameter.
Is it possible and easy to clone my current HD to a new SSD (of the same size ? )to have my PC readied promptly ?

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 05/06/2019 18:17, Artis Sideley wrote:

Thanks to all of you.

The error message is copied pasted from the contextual pop up pane.
Command fdisk displays /dev/sda7 as "Linux swap / Solaris", but unlike with application Disks, the indicated size is 3.8Gb.

You have swap

Command df does not show any line mentionning /dev/sda7.

Swap is not 'mounted'

Command top regularly shows Chromium as the biggest memory user.
I searched ebay RAM module for my Vostro 1510 and found only one offer selling 4Gb Dimm module at the astronomic price of US$100. Other offers only propose 1 or 2 Gb modules.
The S.M.A.R.T test run on my HD shows no worrying parameter.
Is it possible and easy to clone my current HD to a new SSD (of the same size ? )to have my PC readied promptly ?

yes but its slightly more than trivial


Howver I am concrenmed thatt something is going on other than what you think

Fololw R Kettlewells advice. Measure first spend money later


--
"Socialist governments traditionally do make a financial mess. They
always run out of other people's money. It's quite a characteristic of them"

Margaret Thatcher

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 2019-06-05, Artis Sideley <sideley@yahoo.com> wrote:

Thanks to all of you.

The error message is copied pasted from the contextual pop up pane.
Command fdisk displays /dev/sda7 as "Linux swap / Solaris", but unlike with application Disks, the indicated size is 3.8Gb.

Good, so sda7 IS a swap partition.

Command df does not show any line mentionning /dev/sda7.

Good. That means that something has not mounted /dev/sda7

Command top regularly shows Chromium as the biggest memory user.

The other thing is that top is also supposed to show how much swap you
have. The 4th line should start with MiB Mem, and the fifth should start
with MiB Swap . The first entry on that line should tell you how much
swap you have.
Note that the disk size is usually quoted in decimal bytes, not in power
of 2 bytes.
Thus 3.8GB is 3891 MB = 3985000KB= 4080000000 bytes.
There you have the 4GB that disks are advertised as.

I searched ebay RAM module for my Vostro 1510 and found only one offer selling 4Gb Dimm module at the astronomic price of US$100. Other offers only propose 1 or 2 Gb modules.
The S.M.A.R.T test run on my HD shows no worrying parameter.
Is it possible and easy to clone my current HD to a new SSD (of the same size ? )to have my PC readied promptly ?

It may not help that much because the disk bus on an old system is
liable to be slow. Thus the ssd could dump the data much faster than the
disk bus can handle. There should be a bit of an improvement.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 05/06/2019 14.37, Artis Sideley wrote:

On Wednesday, 5 June 2019 14:02:22 UTC+2, Artis Sideley wrote:

Dear all,

I am running Ubuntu 16.04 LTS 64 bits on a DEll laptop with the specs below:
RAM: 4GB
Proc: Intel DUo core 1.8Ghz
Disk: 160 Gb Plain HD

Since One year now on, I have been experienced slow downs with long disk reads, while front running no other software than Chromium. I am not running any significant server process, using my PC as a home terminal.

I have just realised that the HD is partionned with a swap area size 4.1Gb that I cannot activate:

Error activating swap: Command-line `swapon "/dev/sda7"' exited with non-zero exit status 255: swapon: /dev/sda7: swapon failed: Device or resource busy
(udisks-error-quark, 0)

But I remember having activated long ago when I installed the OS.

How to diagnosise what is going on and possibly improve the performance of my PC without any material upgrade? (It would be impossible to add up RAM since all slots are occupied and no larger capacity RAM modules is available)

You can use the "header" of what top displays. Just paste it here and
we'll explain. Or, you can run "free -h" and paste it here so we
explain. It will tell us if the system uses the swap partition and how much.

Also, you can use "sudo /usr/sbin/iotop -o" to see if something is using
the disk a lot.

You can try

lsblk --output NAME,KNAME,RA,RM,RO,SIZE,TYPE,FSTYPE,LABEL,PARTLABEL,MOUNTPOINT,UUID,PARTUUID,WWN,MODEL,ALIGNMENT"

(a single line)

which will tell you what is on your hard disk. Beware of line wraps.

Once you reply, if the swap is not really activated we can help you with
that.

If swap was really activated at system install, one factor that would
disable it would be a disk error.



As others have commented, replacing your hard disk with an SSD unit is
the single change that improves most a computer. If your machine uses
swap the improvement is even more surprising.





--
Cheers, Carlos.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Wed, 05 Jun 2019 13:47:09 -0400, The Natural Philosopher <tnp@invalid.invalid> wrote:

On 05/06/2019 18:17, Artis Sideley wrote:

The error message is copied pasted from the contextual pop up pane.
Command fdisk displays /dev/sda7 as "Linux swap / Solaris", but unlike with application Disks, the indicated size is 3.8Gb.

You have swap

Command df does not show any line mentionning /dev/sda7.

Swap is not 'mounted'

Use "/sbin/swapon -s" to display the current swap available and used.
There are other commands such as iotop, but they are only available if
you have that package installed, whereas swapon is part of the util-linux package which is normally part of the base system.

Regards, Dave Hodgins

--
Change dwhodgins@nomail.afraid.org to davidwhodgins@teksavvy.com for
email replies.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 05/06/2019 19:24, William Unruh wrote:

On 2019-06-05, Artis Sideley <sideley@yahoo.com> wrote:

Thanks to all of you.

The error message is copied pasted from the contextual pop up pane.
Command fdisk displays /dev/sda7 as "Linux swap / Solaris", but unlike with application Disks, the indicated size is 3.8Gb.

Good, so sda7 IS a swap partition.

Command df does not show any line mentionning /dev/sda7.

Good. That means that something has not mounted /dev/sda7

I am not sure you CAN mount a swap partition.



--
The biggest threat to humanity comes from socialism, which has utterly
diverted our attention away from what really matters to our existential survival, to indulging in navel gazing and faux moral investigations
into what the world ought to be, whilst we fail utterly to deal with
what it actually is.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 2019-06-06, The Natural Philosopher <tnp@invalid.invalid> wrote:

On 05/06/2019 19:24, William Unruh wrote:

On 2019-06-05, Artis Sideley <sideley@yahoo.com> wrote:

Thanks to all of you.

The error message is copied pasted from the contextual pop up pane.
Command fdisk displays /dev/sda7 as "Linux swap / Solaris", but unlike with application Disks, the indicated size is 3.8Gb.

Good, so sda7 IS a swap partition.

Command df does not show any line mentionning /dev/sda7.

Good. That means that something has not mounted /dev/sda7

I am not sure you CAN mount a swap partition.

But if he thought sda7 was the swap and it really was not, then it could
be mounted, which would explain the "busy" error message. But I suppose
if it was already mounted as a swap partition and something tried to
mount it again as a swap, you might also get the "busy" error message.






--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Thu, 06 Jun 2019 13:03:48 -0400, The Natural Philosopher <tnp@invalid.invalid> wrote:

I am not sure you CAN mount a swap partition.

The swap file/partition(s) cannot be mounted. Swap can only be enabled
with swapon, or disabled with swapoff.

Regards, Dave Hodgins

--
Change dwhodgins@nomail.afraid.org to davidwhodgins@teksavvy.com for
email replies.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 06/06/2019 18:06, William Unruh wrote:

On 2019-06-06, The Natural Philosopher <tnp@invalid.invalid> wrote:

On 05/06/2019 19:24, William Unruh wrote:

On 2019-06-05, Artis Sideley <sideley@yahoo.com> wrote:

Thanks to all of you.

The error message is copied pasted from the contextual pop up pane.
Command fdisk displays /dev/sda7 as "Linux swap / Solaris", but unlike with application Disks, the indicated size is 3.8Gb.

Good, so sda7 IS a swap partition.

Command df does not show any line mentionning /dev/sda7.

Good. That means that something has not mounted /dev/sda7

I am not sure you CAN mount a swap partition.

But if he thought sda7 was the swap and it really was not, then it could
be mounted,

No, it could not.

It does not have a mountable file system, IIRC



--
The theory of Communism may be summed up in one sentence: Abolish all
private property.

Karl Marx

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 2019-06-06, The Natural Philosopher <tnp@invalid.invalid> wrote:

On 06/06/2019 18:06, William Unruh wrote:

On 2019-06-06, The Natural Philosopher <tnp@invalid.invalid> wrote:

On 05/06/2019 19:24, William Unruh wrote:

On 2019-06-05, Artis Sideley <sideley@yahoo.com> wrote:

Thanks to all of you.

The error message is copied pasted from the contextual pop up pane.
Command fdisk displays /dev/sda7 as "Linux swap / Solaris", but unlike with application Disks, the indicated size is 3.8Gb.

Good, so sda7 IS a swap partition.

Command df does not show any line mentionning /dev/sda7.

Good. That means that something has not mounted /dev/sda7

I am not sure you CAN mount a swap partition.

But if he thought sda7 was the swap and it really was not, then it could
be mounted,

No, it could not.

It does not have a mountable file system, IIRC

Of course it could have. If it is not a swap partition and has say an
ext4 filesystem on it, it could have been mounted. Ie, He could be
mistaken that /dev/sda7 is a swap partition.
All we had to go on was that swapon said it was "busy". That is pretty
minimal information. He asked for how he could debug this. I suggested
tht he look to make sure that that was a swap partition as one of the
first things to do.






--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On Thu, 6 Jun 2019 18:03:48 +0100, The Natural Philosopher wrote:

I am not sure you CAN mount a swap partition.

Well for swap partition to be used, it has to be mounted.

On my installs, I use media label as mount points. Take a look at
this snippet.
$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
├─sda4 8:4 0 40.5G 0 part /
├─sda5 8:5 0 21.5G 0 part /local
├─sda6 8:6 0 22.4G 0 part /accounts
├─sda7 8:7 0 59.4G 0 part /misc
├─sda8 8:8 0 73.2G 0 part /spare
├─sda9 8:9 0 362.2G 0 part /vmguest
├
sdb 8:16 0 931.5G 0 disk
├─sdb1 8:17 0 7.8G 0 part [SWAP]
├

Note the MOUNTPOINT for my swap partition.

The trick is to know the command and 'mount' is not going to work.
$ swapon -s
Filename Type Size Used Priority
/dev/sdb1 partition 8191996 0 -2
indicates swap is mounted at sdb1.

Only way to managing swap mountin is use swapon or swapoff.

--- SoupGate-Win32 v1.05
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On Thu, 06 Jun 2019 16:13:32 -0400, Bit Twister <BitTwister@mouse-potato.com> wrote:

├─sdb1 8:17 0 7.8G 0 part [SWAP]
Note the MOUNTPOINT for my swap partition.

The definition of a mountpoint is a directory used to mount a file system. http://www.linfo.org/mount_point.html

The [SWAP] shown under the mountpoint column isn't a directory, so it is not
a mountpoint. It's just that lsblk authors chose to reuse the mountpoint
column to indicate whether or not the swap has been enabled rather then
add another column or some other way to show that info. If it were a
mountpoint then "ls [SWAP] would show the contents of the enabled swap
rather then whether or not a file by that name exists in the current
directory.

It's just semantics, but when it comes to understanding how linux works
the semantics do matter.

Regards, Dave Hodgins

--
Change dwhodgins@nomail.afraid.org to davidwhodgins@teksavvy.com for
email replies.

--- SoupGate-Win32 v1.05
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On Thu, 06 Jun 2019 16:26:07 -0400, William Unruh <unruh@invalid.ca> wrote:

Anyway, I regard the "busy" error from swapon as an indication that that partition is already mounted, whether as a regularly mounted partition
or as a swap partition. However I have no idea what the program swapon
means by busy. I have not gone into the source code to find out (nor I suspect have any of the contributors to this thread).

Sorry, thought it had been answered. It's caused by swapon running when
the swap has already been enabled.

Regards, Dave Hodgins

--
Change dwhodgins@nomail.afraid.org to davidwhodgins@teksavvy.com for
email replies.

--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)

On 2019-06-06, Bit Twister <BitTwister@mouse-potato.com> wrote:

On Thu, 6 Jun 2019 18:03:48 +0100, The Natural Philosopher wrote:

I am not sure you CAN mount a swap partition.

Well for swap partition to be used, it has to be mounted.

On my installs, I use media label as mount points. Take a look at
this snippet.
$ lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
├─sda4 8:4 0 40.5G 0 part /
├─sda5 8:5 0 21.5G 0 part /local
├─sda6 8:6 0 22.4G 0 part /accounts
├─sda7 8:7 0 59.4G 0 part /misc
├─sda8 8:8 0 73.2G 0 part /spare
├─sda9 8:9 0 362.2G 0 part /vmguest
├
sdb 8:16 0 931.5G 0 disk
├─sdb1 8:17 0 7.8G 0 part [SWAP]
├

Note the MOUNTPOINT for my swap partition.

The trick is to know the command and 'mount' is not going to work.
$ swapon -s
Filename Type Size Used Priority
/dev/sdb1 partition 8191996 0 -2
indicates swap is mounted at sdb1.

Only way to managing swap mountin is use swapon or swapoff.

It is becoming an argument over semantics. I think they are saying it is
not mounted because you cannot mount a swap partition with the command
mount. You are saying it is mounted because the kernel can access it and
it can be mounted with swapon. I would agree with youi. Teh swap is
listed in /etc/fstab, which would usually indicate that those things are supposed to be mounted, but you cannot
argue with definition.

I however would not say that swap is "mounted on " /dev/sdb1. That is
the label for the disk partition. Thus I would not argue that /dev/sda4
is "mounted on " /dev/sda4. It is mounted on the file system point /
So in that sense, /dev/sdb1 is not mounted anywhere on the filesystem.
It is separate. It is swap, which is treated specially by the kernel.


Anyway, I regard the "busy" error from swapon as an indication that that partition is already mounted, whether as a regularly mounted partition
or as a swap partition. However I have no idea what the program swapon
means by busy. I have not gone into the source code to find out (nor I
suspect have any of the contributors to this thread).




--- SoupGate-Win32 v1.05
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On Thu, 06 Jun 2019 16:32:31 -0400, David W. Hodgins wrote:

The definition of a mountpoint is a directory used to mount a file system. http://www.linfo.org/mount_point.html

I thought it a bit ironic to indicate /etc/fstab has the list of
mount points, for example

$ cat /etc/fstab
LABEL=cauldron / ext4 relatime,acl 1 1
LABEL=accounts /accounts ext4 relatime,acl 1 2
PARTLABEL=swap swap swap defaults 0 0
with the second column indicating the mount point.

It's just semantics, but when it comes to understanding how linux works
the semantics do matter.

as does when used within context. :)

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On Thu, 06 Jun 2019 16:56:47 -0400, Bit Twister <BitTwister@mouse-potato.com> wrote:

On Thu, 06 Jun 2019 16:32:31 -0400, David W. Hodgins wrote:

The definition of a mountpoint is a directory used to mount a file system. >> http://www.linfo.org/mount_point.html

I thought it a bit ironic to indicate /etc/fstab has the list of
mount points, for example

$ cat /etc/fstab
LABEL=cauldron / ext4 relatime,acl 1 1
LABEL=accounts /accounts ext4 relatime,acl 1 2
PARTLABEL=swap swap swap defaults 0 0
with the second column indicating the mount point.

From man fstab ...
The second field (fs_file).
This field describes the mount point for the filesystem. For swap partitions, this field should be specified as `none'.

I just tested changing it from swap to none, so it appears the mountpoint
field is ignored for partitions with type swap. While Mageia uses swap
instead of none as suggested by the man page, either works.

Regards, Dave Hodgins

--
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email replies.

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On 06/06/2019 19:16, William Unruh wrote:

On 2019-06-06, The Natural Philosopher <tnp@invalid.invalid> wrote:

On 06/06/2019 18:06, William Unruh wrote:

On 2019-06-06, The Natural Philosopher <tnp@invalid.invalid> wrote:

On 05/06/2019 19:24, William Unruh wrote:

On 2019-06-05, Artis Sideley <sideley@yahoo.com> wrote:

Thanks to all of you.

The error message is copied pasted from the contextual pop up pane. >>>>>> Command fdisk displays /dev/sda7 as "Linux swap / Solaris", but unlike with application Disks, the indicated size is 3.8Gb.

Good, so sda7 IS a swap partition.

Command df does not show any line mentionning /dev/sda7.

Good. That means that something has not mounted /dev/sda7

I am not sure you CAN mount a swap partition.

But if he thought sda7 was the swap and it really was not, then it could >>> be mounted,

No, it could not.

It does not have a mountable file system, IIRC

Of course it could have. If it is not a swap partition and has say an
ext4 filesystem on it, it could have been mounted. Ie, He could be
mistaken that /dev/sda7 is a swap partition.

But he already showed that it said 'I am a swap partition'

So it couldn't have been mounted

Why is this so hard?

All we had to go on was that swapon said it was "busy". That is pretty minimal information. He asked for how he could debug this. I suggested
tht he look to make sure that that was a swap partition as one of the
first things to do.

No. we had a command that showed that it was a swap partrition. i.e.
could not be mounted..e.g.

sudo fdisk -l /dev/sda

Disk /dev/sda: 120.0 GB, 120034123776 bytes
255 heads, 63 sectors/track, 14593 cylinders, total 234441648 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0008587a

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 152162303 76080128 83 Linux
/dev/sda2 152164350 156301311 2068481 5 Extended
/dev/sda3 156303360 234441647 39069144 83 Linux
/dev/sda5 152164352 156301311 2068480 82 Linux swap / Solaris


--
Climate Change: Socialism wearing a lab coat.

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On 06/06/2019 21:26, William Unruh wrote:

It is becoming an argument over semantics. I think they are saying it is
not mounted because you cannot mount a swap partition with the command
mount. You are saying it is mounted because the kernel can access it and
it can be mounted with swapon. I would agree with youi. Teh swap is
listed in /etc/fstab, which would usually indicate that those things are supposed to be mounted, but you cannot
argue with definition.

No. It ius becomeing an argument aboutr egos.

Mounting is a specific term in which *mix systems take a raw drive that
has filesystem on it and incorporates it into the file system tree.

That you did not know this is not 'semantics'. it is ignorance

Ignorance is forgivable. Defending it as 'semantics' is not.


--
"And if the blind lead the blind, both shall fall into the ditch".

Gospel of St. Mathew 15:14

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On Wednesday, 5 June 2019 23:57:47 UTC+2, David W. Hodgins wrote:

On Wed, 05 Jun 2019 13:47:09 -0400, The Natural Philosopher <tnp@invalid.invalid> wrote:

On 05/06/2019 18:17, Artis Sideley wrote:

The error message is copied pasted from the contextual pop up pane.
Command fdisk displays /dev/sda7 as "Linux swap / Solaris", but unlike with application Disks, the indicated size is 3.8Gb.

You have swap

Command df does not show any line mentionning /dev/sda7.

Swap is not 'mounted'

Use "/sbin/swapon -s" to display the current swap available and used.
There are other commands such as iotop, but they are only available if
you have that package installed, whereas swapon is part of the util-linux package which is normally part of the base system.

Regards, Dave Hodgins

--
Change dwhodgins@nomail.afraid.org to davidwhodgins@teksavvy.com for
email replies.

Thanks Dave, here is the output of swapon:

Filename Type Size Used Priority
/dev/dm-0 partition 3998204 721680 -1

It seems fine in term of size.

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On Wednesday, 5 June 2019 23:20:08 UTC+2, Carlos E.R. wrote:

On 05/06/2019 14.37, Artis Sideley wrote:

On Wednesday, 5 June 2019 14:02:22 UTC+2, Artis Sideley wrote:

Dear all,

I am running Ubuntu 16.04 LTS 64 bits on a DEll laptop with the specs below:
RAM: 4GB
Proc: Intel DUo core 1.8Ghz
Disk: 160 Gb Plain HD

Since One year now on, I have been experienced slow downs with long disk reads, while front running no other software than Chromium. I am not running any significant server process, using my PC as a home terminal.

I have just realised that the HD is partionned with a swap area size 4.1Gb that I cannot activate:

Error activating swap: Command-line `swapon "/dev/sda7"' exited with non-zero exit status 255: swapon: /dev/sda7: swapon failed: Device or resource busy
(udisks-error-quark, 0)

But I remember having activated long ago when I installed the OS.

How to diagnosise what is going on and possibly improve the performance of my PC without any material upgrade? (It would be impossible to add up RAM since all slots are occupied and no larger capacity RAM modules is available)

You can use the "header" of what top displays. Just paste it here and
we'll explain. Or, you can run "free -h" and paste it here so we
explain. It will tell us if the system uses the swap partition and how much.

Also, you can use "sudo /usr/sbin/iotop -o" to see if something is using
the disk a lot.

You can try

lsblk --output NAME,KNAME,RA,RM,RO,SIZE,TYPE,FSTYPE,LABEL,PARTLABEL,MOUNTPOINT,UUID,PARTUUID,WWN,MODEL,ALIGNMENT"

(a single line)

which will tell you what is on your hard disk. Beware of line wraps.

Once you reply, if the swap is not really activated we can help you with that.

If swap was really activated at system install, one factor that would
disable it would be a disk error.

As others have commented, replacing your hard disk with an SSD unit is
the single change that improves most a computer. If your machine uses
swap the improvement is even more surprising.

--
Cheers, Carlos.

Ok, thanks Carlos, I got the confirmation that /dev/sd7 is used as swap and mounted. But I cannot use command iotop since it is not installed on my set up.

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On Fri, 7 Jun 2019 00:36:32 -0700 (PDT), Artis Sideley wrote:

Thanks Dave, here is the output of swapon:

Filename Type Size Used Priority
/dev/dm-0 partition 3998204 721680 -1

It seems fine in term of size.

Depends on your usage and applications using it.
As I misunderstand it, if you are going to be using hibernation it needs
to be at least the same size as ram +512meg.

I have seen Oracle installs wanting several times ram in swap size.

when your system has been running for awhile you can check swap usage with
free -m

Here you can see my system is not using swap.

$ free -m
total used free shared buff/cache available Mem: 7975 1273 1288 77 5414 6328 Swap: 7999 0 7999

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Artis Sideley <sideley@yahoo.com> writes:

Ok, thanks Carlos, I got the confirmation that /dev/sd7 is used as
swap and mounted. But I cannot use command iotop since it is not
installed on my set up.

So install it.

--
https://www.greenend.org.uk/rjk/

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On 07/06/2019 09.36, Artis Sideley wrote:

On Wednesday, 5 June 2019 23:57:47 UTC+2, David W. Hodgins wrote:

On Wed, 05 Jun 2019 13:47:09 -0400, The Natural Philosopher <tnp@invalid.invalid> wrote:

Thanks Dave, here is the output of swapon:

Filename Type Size Used Priority
/dev/dm-0 partition 3998204 721680 -1

It seems fine in term of size.

That is not sda7. It is a RAID. You did not say you were using a raid.

That explains the "busy" message.


--
Cheers, Carlos.

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On Fri, 07 Jun 2019 03:00:08 -0400, The Natural Philosopher <tnp@invalid.invalid> wrote:

No. we had a command that showed that it was a swap partrition. i.e.
could not be mounted..e.g.
sudo fdisk -l /dev/sda

The fdisk command is just showing that there is a partition with the
the type specified in the partition table as swap. It doesn't prove that
the partition has had the mkswap command run on it, so it could contain
a mountable filesystem despite the partition table entry having been
changed.

The only way to prove it does contain a swap is to either inspect it
with a hex editor, or by trying to enable it using the swapon command.

The same for proving whether or not it contains a mountable filesystem.
Linux doesn't care what the partition table says. If you try to mount
it, linux will mount it if the filesystem type actually in the partition matches what's specified in the mount command or in the fstab entry. If
it doesn't match, the mount will fail.

Regards, Dave Hodgins

--
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email replies.

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On Fri, 07 Jun 2019 04:45:55 -0400, Carlos E.R. <robin_listas@es.invalid> wrote:

On 07/06/2019 09.36, Artis Sideley wrote:

On Wednesday, 5 June 2019 23:57:47 UTC+2, David W. Hodgins wrote:

On Wed, 05 Jun 2019 13:47:09 -0400, The Natural Philosopher <tnp@invalid.invalid> wrote:

Thanks Dave, here is the output of swapon:

Filename Type Size Used Priority
/dev/dm-0 partition 3998204 721680 -1

It seems fine in term of size.

That is not sda7. It is a RAID. You did not say you were using a raid.
That explains the "busy" message.

The dm device indicates it's a device mapper device. While that could be
raid, it could also be an lvm logical volume, or a loop mounted device
such as would be used for an encrypted swap.

Regards, Dave Hodgins

--
Change dwhodgins@nomail.afraid.org to davidwhodgins@teksavvy.com for
email replies.

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On 07/06/2019 09:39, David W. Hodgins wrote:

On Fri, 07 Jun 2019 03:00:08 -0400, The Natural Philosopher <tnp@invalid.invalid> wrote:

No. we had a command that showed that it was a swap partrition. i.e.
could not be mounted..e.g.
sudo fdisk -l /dev/sda

The fdisk command is just showing that there is a partition with the
the type specified in the partition table as swap. It doesn't prove that
the partition has had the mkswap command run on it, so it could contain
a mountable filesystem despite the partition table entry having been
changed.

Hasve you tried mounting a partition treated in this way?

The only way to prove it does contain a swap is to either inspect it
with a hex editor, or by trying to enable it using the swapon command.

The same for proving whether or not it contains a mountable filesystem.
Linux doesn't care what the partition table says. If you try to mount
it, linux will mount it if the filesystem type actually in the partition matches what's specified in the mount command or in the fstab entry. If
it doesn't match, the mount will fail.

Regards, Dave Hodgins

--
"A point of view can be a dangerous luxury when substituted for insight
and understanding".

Marshall McLuhan

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On 2019-06-07, The Natural Philosopher <tnp@invalid.invalid> wrote:

On 06/06/2019 19:16, William Unruh wrote:

On 2019-06-06, The Natural Philosopher <tnp@invalid.invalid> wrote:

On 06/06/2019 18:06, William Unruh wrote:

On 2019-06-06, The Natural Philosopher <tnp@invalid.invalid> wrote:

On 05/06/2019 19:24, William Unruh wrote:

On 2019-06-05, Artis Sideley <sideley@yahoo.com> wrote:

Thanks to all of you.

The error message is copied pasted from the contextual pop up pane. >>>>>>> Command fdisk displays /dev/sda7 as "Linux swap / Solaris", but unlike with application Disks, the indicated size is 3.8Gb.

Good, so sda7 IS a swap partition.

Command df does not show any line mentionning /dev/sda7.

Good. That means that something has not mounted /dev/sda7

I am not sure you CAN mount a swap partition.

But if he thought sda7 was the swap and it really was not, then it could >>>> be mounted,

No, it could not.

It does not have a mountable file system, IIRC

Of course it could have. If it is not a swap partition and has say an
ext4 filesystem on it, it could have been mounted. Ie, He could be
mistaken that /dev/sda7 is a swap partition.

But he already showed that it said 'I am a swap partition'

Uh, He showed that AFTER I asked him to and after I asked him to look to
see if sda7 was mounted on a file. Yes, he did show that, so I would not
have him look at sda7 now anymore. But it was everyone's reaction that
my original request was silly that I was trying to defend against.
Since the OP also only responds to some requests, having redundancy in determination is not a bad thing.

So it couldn't have been mounted

Yes. we know that now. We did not at first.

Why is this so hard?

Not hard at all, as long as people read, and remember history.

All we had to go on was that swapon said it was "busy". That is pretty
minimal information. He asked for how he could debug this. I suggested
tht he look to make sure that that was a swap partition as one of the
first things to do.

No. we had a command that showed that it was a swap partrition. i.e.
could not be mounted..e.g.

No, we did not.

sudo fdisk -l /dev/sda

After I asked him to run exactly that command.
.

Disk /dev/sda: 120.0 GB, 120034123776 bytes
255 heads, 63 sectors/track, 14593 cylinders, total 234441648 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0008587a

Device Boot Start End Blocks Id System
/dev/sda1 * 2048 152162303 76080128 83 Linux
/dev/sda2 152164350 156301311 2068481 5 Extended
/dev/sda3 156303360 234441647 39069144 83 Linux
/dev/sda5 152164352 156301311 2068480 82 Linux swap / Solaris

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On 07/06/2019 12.54, David W. Hodgins wrote:

On Fri, 07 Jun 2019 04:45:55 -0400, Carlos E.R.
<robin_listas@es.invalid> wrote:

On 07/06/2019 09.36, Artis Sideley wrote:

On Wednesday, 5 June 2019 23:57:47 UTC+2, David W. Hodgins  wrote:

On Wed, 05 Jun 2019 13:47:09 -0400, The Natural Philosopher
<tnp@invalid.invalid> wrote:

Thanks Dave, here is the output of swapon:

Filename                Type        Size    Used    Priority
/dev/dm-0                                  partition    3998204   
721680    -1

It seems fine in term of size.

That is not sda7.  It is a RAID. You did not say you were using a raid.
That explains the "busy" message.

The dm device indicates it's a device mapper device.

In my system, those are under "/dev/mapper/"

While that could be
raid, it could also be an lvm logical volume, or a loop mounted device
such as would be used for an encrypted swap.

Yes, you are right, raid is "/dev/md0" - same letters but not the same
thing.

In any case, it explains the busy message. The underlying partition is
being used by the device mapper.

--
Cheers, Carlos.

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On Fri, 07 Jun 2019 09:59:47 -0400, The Natural Philosopher <tnp@invalid.invalid> wrote:

On 07/06/2019 09:39, David W. Hodgins wrote:

On Fri, 07 Jun 2019 03:00:08 -0400, The Natural Philosopher
<tnp@invalid.invalid> wrote:

No. we had a command that showed that it was a swap partrition. i.e.
could not be mounted..e.g.
sudo fdisk -l /dev/sda

The fdisk command is just showing that there is a partition with the
the type specified in the partition table as swap. It doesn't prove that
the partition has had the mkswap command run on it, so it could contain
a mountable filesystem despite the partition table entry having been
changed.

Hasve you tried mounting a partition treated in this way?

I've seen it happen (unintentionally). Just tested in a virtualbox guest snapshot to confirm it's still the case.

WARNING. Be careful which program is used to change the partition table. WARNING. Most partition managers will helpfully format the partition when WARNING. the type is changed.

Also please note this is about the kernel being able to use a partition
where the type in the table is not the same as the contents of the
partition. Many programs such as grub will complain, and the system will
fail to boot if the partitions it's using have a mismatch.

After change the partition type for sda2 from 83 to 82 using cfdisk ... [root@x6v ~]# fdisk -l |grep a2
/dev/sda2 33527808 33554431 26624 13M 82 Linux swap / Solaris [root@x6v ~]# mount /dev/sda2 /a2
[root@x6v ~]# mount|grep a2
/dev/sda2 on /a2 type ext4 (rw,relatime,data=ordered)
[root@x6v ~]# df|grep a2
/dev/sda2 12M 116K 11M 2% /a2

After rebooting the guest ...
[root@x6v ~]# mount /dev/sda2 /a2
[root@x6v ~]# mount |grep /a2
/dev/sda2 on /a2 type ext4 (rw,relatime,data=ordered)
[root@x6v ~]# fdisk -l /dev/sda|grep a2
/dev/sda2 33527808 33554431 26624 13M 82 Linux swap / Solaris

Note: sda2 is not listed if /etc/fstab.

cfdisk is a partition table editor, it doesn't format the partitions, just edits the table.

Regards, Dave Hodgins

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