Recommended Buffer drive size?

[bighick]

Hello! On my system i have 10 tuners. At times I may use all of them at once which puts a pretty large I/O onto my old spinning disk and NPVR crashes sometimes (I will get logs next time!). My question is how large should my buffer disk be? At times I wont change channels for 5 or 6 hours. Channels are a mix of MPEG and H264, 720p and 1080i. On hand I have a 120gb ssd or could do like 32gb of ram disk.

[mvallevand]

The buffer directory is for live TV. The default is 20 minutes buffering which for 1080i could be around 3GB. (there are four files) and likely closer to 1GB for other formats. In EPG mode the rate is buffering however many shows you watch. Normally I would say 32GB would be enough for 10 tuners but there are instances where NextPVR fails to delete the old files so you might fill a ram drive up. Also in your example on 6 hr live tv session in EPG mode could be 48GB

If you are also transcoding for the web server or android/ios or timeshifting to Kodi, you need to doouble the space requirments, but the transcoding drive is hardcoded to the system drive so it can't go to a ram disk.

If you have 10 different people streaming live that doesn't sound like personal use for the NextPVR license.

Martin

[bighick]

Makes sense thanks. Sounds like the 120gb SSD should be more than enough.
It is personal use, no NextPVR stream has ever left my house. My basement cave has 4 TVs on one wall plus others scattered throughout the house and possibly a recording or two going on.

[Bobins]

I use an SSD as the main recording directory to avoid problems with disk I0 / head thrashing wear & tear / fragmentation etc. Once the recording finishes (and as long as it's not being currently watched), the recording is moved to a hard drive raid.
The hard drives spin down when not in use.
I adopted this for two reasons.
1)performance when recording multiple HD streams which may be concurrent with playback and
2) reducing hard disk wear & tear on the hard disks having experienced multiple hard disk failures in the past. Rebuilding multi TB raids is no fun

Modern SSDs cope well with the write/delete wear cycle.

[Lao Pan]

Once the recording finishes (and as long as it's not being currently watched), the recording is moved to a hard drive raid.

May I ask how you are handling the Moving?

I am using a 60gb SSD for live TV which would be useful to use for all recordings to stop Fragmentation on the 2TB recordings drive. Perfect disk runs for about 5 hours to get it defragged.

[Bobins]

I have a couple of small scripts which handle the move (and create a log file) and these are triggered from PostProcessing.bat.
I also run a scheduled script which concats & cleans up the created log files each day
Happy to share if you were interested.

[Lao Pan]

I have a couple of small scripts which handle the move (and create a log file) and these are triggered from PostProcessing.bat.
I also run a scheduled script which concats & cleans up the created log files each day
Happy to share if you were interested.

Yes please - most definitely.

Thanks

[Bobins]

OK See attached

In my case the Recording cache is my F: drive and the Recording store is the R: drive.

The Postprocessing.bat file calls the "Move" script. This handles the move after testing that the file exists and isn't locked by the fact you're watching whilst it was recording.
The "Move2" is triggered by "Move" if the lock condition is true and waits for the file to become unlocked before completing the move.

Log files are placed in a directory called "Move" under the main NPVR Log file directory.

"Tidyuplogs" is scheduled to start (in Windows scheduler) just before midnight. It sets up some parameters then call "Tidyup".
"Tidyup" concats the individual "Move" log files into a single daily log file then cleans up. It also removes any leftover files in the Live TV temporary directory (Kodi had a habit of causing leftover files here).

All the .bat script files go in the NPVR script directory

Any questions....please ask.

[mvallevand]

How does recording to an SSD and moving it is post processing improve things? Seems like it just delays writes for an hour or so and creates more work for the SSD.. Certainly a live TV SSD makes sense logically as does adding multiple recording drives.

Martin

[Bobins]

Martin.

The improvement is reduced wear & tear on the mechanical hard drives which can also power down when not in use. Copying from SSD to hard disk generally ends up with contiguous files on the hard disk so less fragmentation.
In my household it is typical for multiple HD recordings to be happening at the same time as recording playback. On a hard disk this would result in lots of disk head movement and increases the wear.
Ultimately I chose this after experiencing several hard disk failures and the pain of trying to recover lost recordings. I also wanted to ensure that I/O wasn't a problem given most recording/playback is now in HD format so quite large.

It is fair to say that I did this at a time when SSDs were quite expensive in comparison to Large Hard drives.
Given large terabyte SSDs are now within the purchase power of domestic users, simply putting it all on an SSD may be more sensible.

In my case the 4Tb raid (which is nearly full) isn't really practicable (or affordable) on SSDs.

Ray