SageTV playback stalls when mover running

[glenner]

I've noticed since upgrading to unraid 6.7.2 a few months ago that SageTV playback now freezes or stutters at exactly midnight every day. This lasts 5-10 minutes, and then playback recovers. Playback recovers by actually going high speed with no sound for several minutes until it catches up. After the 5-10 minutes, I usually stop and restart playback instead to resume normal playback.

I checked the unraid server log and noticed that the mover is running at that time.

My mover is set to run every 4 hours and since many shows are recorded during primetime and I'm also watching TV at midnight, I see the issue then. I takes about 5-10 minutes to copy a few GB of shows from the cache to the array.

My config is in my sig and my hardware is pretty decent... So I'm hoping this should be a tuning issue of some kind.

Has anyone else observed this and figured out a way to performance tune the system so this issue is mitigated?

[wayner]

Why record to the cache rather than straight to the array? That's what I do. I don't record a ton of shows, but I will have had instances where I simultaneously record two shows from my HD-PVRs and one from OTA.

[glenner]

I have 4 tuners and so could conceivably record 4 HD shows at once, though I think realistically I'd only ever have 2 recordings going simulaneously, and could also be playing back 1 show at the same time.

Just for performance reasons I assumed it makes sense to record to the cache, and have the mover go on a schedule... I've always had it this way for a few years now.

I also thought this would result in less wear and tear on the array, or at least the parity drive.

Is this thinking flawed? Most people record straight to the array?

[EnterNoEscape]

I record to the cache too, but I have the mover set to run once a day at 4am. When it is running, it can really affect playback, so I scheduled it for a time when no one is normally trying to watch TV.

The reason I used the cache is to reduce the amount of time all the disks are spun up. I have my recordings only go to one disk in my array, so usually only one disk is actually spun up at any given time. Limiting my recordings to one disk also greatly decreases any delays in SageTV navigation related to a disk spinning up.

Edit: I want to note that I've also see the described behavior when the mover wasn't running. It turned out to be a disk in my array was failing (not the recordings disk).

[glenner]

Thanks. Good to know that writing recordings to the cache is sensible. It seems to me that's the correct setup for SageTV. I also have a single drive in the array where I move my recordings to. While the ability to stripe a share across multiple drives is potentially a useful feature of unraid, I just prefer to know which physical drive my stuff is on. If ever I need to somehow recover some files, I just want to have my folders (shares) on one drive, and not spread out over several drives. I have sagetv recordings on one drive, movies on one drive, home movies on another, photos on another, etc.

In any event, I'll try setting the mover to once a day, early AM and see if that works. I think I had a problem with that as my cache is 250GB, and 100GB is constantly in use for appdata and other stuff, and so the recordings may actually fill my cache. I recorded the Superbowl the other day on 2 channels in case one channel crapped out, and that takes 50GB total.

I'll give this a shot...