QNAP 251+ struggling with large files

dr_jon

Okay, I phrased that poorly, apologies. NAS have a setting to spin down the disks after a period of inactivity. That may be set to 30, 60 or more minutes. I've found my media player can read in a big chunk of a file when it starts playing and not go looking for the next part for 45 minutes, or more if you hit pause to go get a coffee, or the data rate is low. The NAS sees no network activity for an hour (or whatever the limit is) and so spins down the drives. The network player gets towards the end of its buffer and so asks for some more data. The NAS then starts spinning up its drives, which they usually do one at a time. Which doesn't happen before the Media Player runs out of data.
(This was a real problem I had.)

Coulson

Oh OK. That is possible but I've never seen it. Is this an old NAS?

Sloppy Bob

Certainly with my NAS if I pause it for a longer period of time, when I come back it plays for a few seconds, stops, buffers for 10-20 seconds while the disks spool back up and then it continues playing.

Coulson

Which NAS are you guys using? I run 4k HDR ATMOS streams and the only time I have being issues is on wifi but that's because it's wifi.

Sloppy Bob

I'm using a Synology Ds1817

When I say longer periods I don't mean 2 mins make a cup of tea paused. More if someone comes to the door and it's sitting paused for 20mins .

Even then it's not a problem, it just takes 10-20 seconds for the NAS to wake up again and continue as before. It doesn't stop randomly and do this, only when I pause it long enough for the disks to go to sleep and even that's if the NAS isn't doing anything else. If it's running other apps, copying etc it doesn't do it.

It's a feature of a NAS to save power. If it's not doing anything why have the whole thing running?

dr_jon

I have NAS of assorted ages

But it's quite straightforward, if you have a disk spin-down time set on any NAS then not accessing it for that long will cause a spin down. All my NAS spin their disks up one at a time, which takes a while. It's really down to how much data a media player buffers and if you nip off for a minor distraction that takes some time.

Coulson

I know the feature as it's pretty standard. Maybe I haven't left my drives in pause for long enough. I think I didn't read your last comment properly when you said:

"Even then it's not a problem, it just takes 10-20 seconds for the NAS to wake up again and continue as before. It doesn't stop randomly and do this".

That is indeed pretty standard. I got caught up in your original comment about buffering. I need to pay better attention.

Coulson

You guys have been pretty clear about what you are talking about. I was mixing this up with other conversations I had before about buffering while playing media.

TKDdude

Hi,
Just seen this so not sure whether you've solved your problem yet, but thought it may be helpful to recount my experience serving files directly to an LG OLED 55E7 from a DLNS server (UMS) running on a PC. The PC runs a 40TB 5 drive RAID 5 array on a HW card (Areca 1882) so can stream files at 300-600MB/s, depending upon their location in the array.

I've also experienced occasional stuttering on 4k movies, and it turned out to be due to other activities on the PC causing the RAID array to reach 100% disk activity. The offending processes comprised both a torrent client (mostly solved by tweaking the cache settings) which can easily be suspended, and occasionally UMS housekeeping activites (mostly solved by tweaking process priorities).

My point is really that although a fileserver can stream files at rates way above those required for video playback, it can only do it sequentially. Once some random file accesses are mixed in the fileserver streaming rate can easily drop by orders of magnitude. This can also occur if for example there are slow sectors on the drive(s). 4KB Random access read throughput for an 8TB WD Red drive is circa 1MB/sec,

So, if its not your USB to network adaptor, it might be worth checking disk utilisation on the QNAP, if it provides the tools to do so.

Alternatively, steaming the files from your QNAP to a PC/Mac for comparison (via GBit ethernet and/or your USB adaptor) might also help reveal any problems. On Windows a simple file copy will allow you to monitor the transfer speed and confirm/eliminate this as a potential issue. Although I'm not familiar with OSX, I would guess it provides similar facilities.

TKDdude

Sorry Xar - missed your comment above - glad you've identified the problem. Renders my comment above academic interest only .