Plex bogs down

S

steakman1971

2[H]4U
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Nov 22, 2005
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I'm looking for some input on how to troubleshoot an occasional problem I have watching media using Plex to stream ripped movies. Most of the movie will be fine - this tends to happen towards the last 15-30 minutes of the movie (and not consistently).
My system is a little complicated, but not overly so.
File server is a Core2Quad, 6 gigs of ram, runs Ubuntu 12.x. The media files are stored on a SnapRAID array. This system also runs SABnzb, Couch Potato, and Sickbeard. Checking "uptime" when this happens - the load is very low.
Code: 
chris@minty:/data$ uptime
 22:18:48 up 18 days, 11:35,  1 user,  load average: 0.00, 0.03, 0.05

Next, Plex Server is running on a different system. It's Windows 7, 8 GB RAM, dual-core Athlon processor. This has Norton 360 on it, but should not have been scanning at the time. When I check task manager, this system is typically idle.

My TV has a Roku 3. The Roku 3 has an ethernet cable to a gigabit switch. I'm also running it at 720p resolution. I had this on wifi and thought maybe that was an issue. Still happens with the wired connection. (Also lowed from 1080p to 720p to see if that might help). Both computers are wired and have gigabit ethernet.

Any thoughts on what I might look for? I don't know if I can see a "log" for the Roku. Possible it's having issues with the encoding.
The last movie I watched was an mkv, supposed to be a 1080p rip. Not sure what is was encoded with.
 
On my plex server, I typically see 2-3 processors pegged (out of 48) when transcoding a video for a Roku 3. They're Athlon/Opetron cores running at 1.9GHz, so, roughly equivalent to what you're using. Might be interesting to install plex on the file server to see if the C2Q will fix it up....
 
I moved Plex over to my Core2Quad. I watched a single movie - during the movie, every 10-15 minutes it dropped me out to Plex's main menu saying "Video unavailable". I'll have to see if I can figure out what's going on here - that system is running other services that could fire up every now and then causing some of the cores to be unavailable. When I manually monitor it, it's typically idle.

I switched back to my dual-core Athlon for the remainder of the video - it did not pause/stutter.

I'm going to log my system performance on my Athlon system and see if it is pegging out the CPU.

I'm planning on an upgrade in the next 4-6 months. So, this problem might go away after that anyway. Thanks for the feedback.
 
What's the SNAPraid backend? Wondering about all that stuff running on it as well.

Where's the transcoding folder on the backend storage or on the Windows 7 box running Plex?
 
I verified that Plex and the Plex transcoder are pegging my Athlon dual core. I checked it out during the movie and saw processes. Weird thing - it doesn't seem to happen until maybe 75-80% of the video is complete.

SnapRAID gives a relatively low resource RAID file system. It is not using much CPU when Plex is streaming - disk IO seems pretty low last I checked. I did a quick check running "uptime" and "top" while the other computer was bogged down - not much of anything.

The movies are 1080p rips. My tv is 1080p. Do I even need to mess with transcoding or can I go to a direct play mode? I should probably read up on some docs at this point.
 
Direct play is almost always better if you have the network bandwidth for it. Let the client device handle the decode.

C2Q 8GB boxes are under $200 on eBay. Might be a good upgrade.
 
You have a quad core serving files which requires no cpu, and a dual core transcoding, which is mostly cpu.

This doesn't seem backwards to you?
 
Long story about my computer setup. I know the C2Q is better for this task than the Athlon system.
I'm still experimenting with the C2Q - it keeps saying the videos are unavailable. Not sure what's up with it.
 
Again, what's the SNAPraid backend, how many disks? Where is your transcoding folder on each of the systems when you're testing?
 
whats running on your snapraid?

you say you got all those services in the background running... are they unzipping a file or something large in the background?
 
Hey whats the memory on your plex server? I have a Phenom x4 955 box that just gets destroyed when transcoding because it only has 2gb with integrated graphics so 1.8gb really... (also on windows) but one it hits the limit it starts using virtual memory and I see similar behavior.

You might also check in the server option if it is trying to build media indexes
I think its under settings -->server-->library (advanced ) -->Generate media index files during scans
in 9.11.7
also if you have auto updating and a folder loop like you map tvshows to one lib and tvshows\alf to another then the auto update will trigger a loop on updates...
 
Snapraid is my disk array. It has 6 disks comprising it - it stores all of my media files. It's pretty low overhead. Disk parity is down in the middle of the night (and I'm not up when this happens).

I do have Couchpotato, Sickbeard, and SABNZB running - but they are typically idle. I've logged my Linux servers performance and compared it to the time frames. (I'm using top, uptime, and I ran a few disk io tools for a while).

I'll check the transcoding folders. I think my Linux server has this going to a 1.2TB drive that is not part of the snapraid array. My Athlon computer has an SSD and a 2TB drive in it - not sure which drive.

I've not seen memory being low on either machine. My Athlon has 4GB (and has over 2gb free when Plex is bogged down), My Ubuntu system has 6gb. It's been showing plenty of available RAM.

The strange part is the problem does not occur until about 90 minutes into a file. I'm not sure if plex does an fopen() on the file and starts from the beginning until the end? I'd be curious to know how it chunks the video stream for encoding. Not that it would help, just a curiosity.
 
Dont quote me on this but i think you can change the transcode chunk size or maybe its the buffer. I havent really messes with those yet. Also are using the default h264?
 
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