"Spread Mode" question

[ttfitz]

Looks like a lot of good stuff in the update, will have to try out soon. I did have a question about this "spread mode" option, recording on the drive with the most space available.

Back when I had a DVR with an external hard drive, I would run into a problem, when it used a similar scheme. I was often very close to full on both drives. Let's say an hour long HD program takes about 5GB of space. Drive 1 has 8GB free, drive 2 has 6GB free. On my DVR (where, I should point out, it was difficult to determine where the free space was), if I had two hour long programs scheduled to start at the same time, both would look at the situation, see that Drive 1 had the most space, and record both programs to it, of course failing before the hour was up. It had no concept of the other tuner being at work, and this didn't just apply to simultaneous starts, it also didn't note programs already in progress on a particular drive.

So, is NextPVR's implementation similar, that it only looks at the current situation, or does it somehow take into account things that are happening?

Thanks.

[johnsonx42]

It's a simple comparison at the moment the recording is starting, and takes nothing else into account.

It does see the space already used by a recording in-progress though (because Windows reports it), so if you have hour-long recordings going on one drive, then more recordings launching on the half-hour mark, those new recordings may be pushed to the other drive by the space already consumed. I saw this several times during my testing.

[johnsonx42]

In the future I'd like to see a bit of logic where NRecord "mentally" subtracts 2GB of space for each recording in-progress on a particular drive, then does the space comparison. So you start with 20GB free on C: and D:, and the first recording starts on C:. Then another recording is about to start at the same time, NRecord subtracts 2GB from the C: drive space and concludes D: now has the most space so it starts the next recording there. Then if there's a 3rd recording starting, both drives would get the 2GB deduction, and it would default back to C:, and so on.

This would have the double-bonus effect of "load balancing" recordings across the drives (as long as their starting free space is close to equal), and would handle the space-constrained situation ttfitz described by predicting some use of space by the recording(s) in-progress.

[ACTCMS]

The running out of space problem will only be solved when NPVR is clever enough to predict that you are about to run out of space (based on your normal usage profile) with about a week to go. It could then call your favourite mail-order store, order a bigger hard disk, sign for it on receipt and install it as soon as there are no recordings in progress.

Until that day, you just have to stay on top of your recording space... or get bigger disks... or both...

Alex

[johnsonx42]

The logic I want is primarily for load balancing, it just so happens it will help a little if you're down to your last few GB of disk space too. Remember, the more space you have, the more stuff you record and the longer you keep it, so that dual 2TB drives will become just as full as dual 320GB drives.

[Reddwarf]

the more space you have, the more stuff you record and the longer you keep it, so that dual 2TB drives will become just as full as dual 320GB drives.

Tell me about it

[johnsonx42]

This is the part sub hates about adding a new feature... as soon as he does, people immediately want it to be better (people? usually me ). During pre-release testing within an hour of the update that finally made this work, I was asking him to add per-drive "reserve space" settings so that it wouldn't use up all the space on a particular drive (in my case my C: drive and main recording drive are both 320GB WD GP-AV drives, so I have plenty of space for recordings on C: but of course I don't want C: getting down to zero). Now I'm back with load-balancing logic.

The "spread" feature is fantastic either way.

[ttfitz]

The running out of space problem will only be solved when NPVR is clever enough to predict that you are about to run out of space (based on your normal usage profile) with about a week to go. It could then call your favourite mail-order store, order a bigger hard disk, sign for it on receipt and install it as soon as there are no recordings in progress.

Alex

Ooo, yeah, I like that - post that over on the Wishlist board!

And Mr. Johnson is correct, mo disk space, mo problems.

-Tim (who has about 5TB of space devoted to recordings, and still is racing to watch stuff to make room)

[ACTCMS]

Ooo, yeah, I like that - post that over on the Wishlist board!

Seriously though... if NPVR could do exactly what you asked for in your opening post, your two recordings might be fine, but what happens to any subsequent recordings?

IMHO it's really not worth the coding effort just to save two extra recordings. Folks really need to take responsibility for their own recording space. After all, NPVR now has the Spread feature and it's had the series Keep so many episodes feature for some time.

PS could I suggest that Tim gets a second NPVR system going so he can watch two recordings at the same time?

[bgowland]

The concept of load-balancing is definitely a good one although predicting disk space required for the duration of a recording would never work accurately. The only way sub could implement that would be using a user configurable "fiddle-factor" or fuzzy logic, i.e., the user sets something which says 1 hour @ HD = X GB of storage requirement. I don't see that happening (or being reliable).

On the subject of load-balancing, however, perhaps using the logic used for allocating recordings to different tuners could also be used to provide a reliable spread. I do think it would be more complex to implement than the general theory appears to be though.

Cheers,
Brian