I'm getting intermittent continuity errors on tuners connected to TVHeadend
on a Pi4.


For several years I've been running TVHeadend on Pi4, with a PCTV 491e
DVB-S2 tuner and a Hauppauge WinTV DualHD DVB-T2 tuner, writing to a USB
caddy containing a spinning HDD. All the USB devices are connected to
separate USB sockets on the Pi: I'm not multiplexing several devices via a
hub onto a single USB socket on the Pi.

Mostly this works perfectly, but every now and again I get continuity
errors, maybe 50-150 per hour of recording, when normally I get zero for DVB-S2, and 0 to 5 per hour for DVB-T2. The reported signal strength and SNR when I get glitches (on the Status | Stream tab) seem the same as normal: around 11-12 dB (SNR) and -30 dBm (strength) for satellite and around 25 dB
/ -42 dBm for terrestrial.

The HDD is a standard Sata 3 spinning HDD: Samsung HD161HJ, and the powered
USB caddy is a WAVLINK one. (*)

I'm wondering whether it's not so much a reception problem as a USB-transfer problem, either from tuner to Pi or Pi to HDD.

Once the problem happens, it affects all tuners and all recordings made
until I reboot (without powering down Pi or HDD caddy). Rebooting sets the Status | Stream error counters to zero, but more importantly seems to
prevent future errors occurring - for a few days or weeks. I've got into the habit of rebooting the Pi every few days, just in case...

Before I go through the hassle of changing components (tuners, USB caddy interface, HDD) one by one, I wanted to check whether anyone else with a similar setup has experienced (and maybe fixed) this problem.




Are there any solid-state HDDs which are suitable for repeated writes and
then deletes of large files, such as you'd get on a PVR. I tend to use the
Pi's HDD just for temporary storage, copying and editing out commercials in recorded programmes onto a Windows PC for long-term storage. Hence the Pi's
HDD does not need to be large - 100 GB is fine.


(*) I found out by bitter experience that a powered hub with a USB HDD (as opposed to a USB-SATA interface in a caddy containing a SATA HDD) had
problems with the Pi 4: the Pi would not boot if the USB hub was powered on
at the time (as would happen if the power to everything came back on simultaneously after a power cut). When the Pi had hung, it would resume booting the instant the powered hub was unplugged either from the Pi's USB
or else from its power supply. This seems to be a Pi 4 "funny": the same USB hub worked fine with a Pi 3B+. But that's an aside.
--- SoupGate-Win32 v1.05
* Origin: Agency HUB, Dunedin - New Zealand | Fido<>Usenet Gateway (3:770/3)