Question about Server Usage and Plex Transcoding

OK my unraid server has an Intel® Core i7-4770K CPU @ 3.50GHz with 16GB RAM. I upgraded to this thinking it would be powerful enough to simultaneously transcode multiple Plex streams at a time. I have a few friends that watch Plex off my server and the streams need to be transcoded. In our home on the LAN we have two Roku 3's and a htpc.

We were having constant buffering issues and I went into the Unmenu top processes and it shows python and plex new trancoders as the top processes. I know that Sabnzb was running and so were 2 plex transcodes at the same time. I still think that my cpu should be able to handle that. I was figuring that the i7 was going to be able to do more than 4 trancodes at a time.

Looking for any suggestions and tips to correct this. THanks

The CPU upgrade was def the right way to go - https://plexapp.zendesk.com/hc/en-us/articles/200250377-Transcoding-Media

With being on version 5.0.5 and it being a 32-bit OS, it can only allocate up to 4GB of your 16GB of RAM.  Moving over to 6beta3 will allow all of that be allocated.  You can't use the default plex installer, but here is one that has been made for 64 bit - https://forums.plex.tv/index.php/topic/96024-plex-media-server-for-unraid-60-x86-64/#entry561614 .  There are directions somewhere on how to build your own 64bit build with the newer plexpass releases. 

I have about the same setup (if not a bit slower) and I've had 7 sessions going, with 5 of the being remote and most of those needing transcoding. I have sabnzbd pause as it unpacks/moves my new downloads. 

Is plex running on a cache drive or running on the array?  Have you tried using the "new" encoder in plex?

Are you sure transcoding is your bottleneck?

I haven't tried 3+ transcodes yet but I have Plex installed in an ArchVM and so far, it's been running like a dream. I have the same CPU you have but 32GB and 64bit.

The CPU upgrade was def the right way to go - https://plexapp.zendesk.com/hc/en-us/articles/200250377-Transcoding-Media

 

With being on version 5.0.5 and it being a 32-bit OS, it can only allocate up to 4GB of your 16GB of RAM.  Moving over to 6beta3 will allow all of that be allocated.  You can't use the default plex installer, but here is one that has been made for 64 bit - https://forums.plex.tv/index.php/topic/96024-plex-media-server-for-unraid-60-x86-64/#entry561614 .  There are directions somewhere on how to build your own 64bit build with the newer plexpass releases. 

 

I have about the same setup (if not a bit slower) and I've had 7 sessions going, with 5 of the being remote and most of those needing transcoding. I have sabnzbd pause as it unpacks/moves my new downloads. 

 

Is plex running on a cache drive or running on the array?  Have you tried using the "new" encoder in plex?

Yes I am running plex on cache drive and using the new encoder

Are you sure transcoding is your bottleneck?

Only use plex, sabnzb and sickbeard on server

But what is your internet UPLOAD speed?  Your friends will buffer if your connection is slow.

But what is your internet UPLOAD speed?  Your friends will buffer if your connection is slow.

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Well I gotta tell ya, your first best bet is to figure out why you are even transcoding to the Roku3.  I have very few sources that need to transcode.  Only the fattest of BD rips forces a transcode (think: Avatar like bitrates).  Just about anything from the scene direct plays, as do most of my full rate BD rips.  That include DTS-HD and TrueDTS which just get stripped, but not transcoded, down to DTS.  And of course even if they were transcoded, audio takes very little cpu.

Are you sure you are indeed transcoding to the Roku3?  You can easily check during playback by hitting the down arror button o nthe remote to bring up the info HUD.

Another vote for going to 64-bit Beta3 ... even according to the plex devs, 64-bit helps transcoding beyond just more memory because of the larger register space and optimizations in the 64-bit transcoder code.

That said, your CPU is rated for about 9000 passmarks so you are right that you should indeed be able to transcode about 6 streams assuming no other load.  But at that point I wonder if you still might start hitting HD and limits if you're trying to serve it all from the same HD and maybe even memory bandwidth [shrug].

Something that comes to mind: Where do you have your temp directory located?

Well I gotta tell ya, your first best bet is to figure out why you are even transcoding to the Roku3.  I have very few sources that need to transcode. 

This!  All of my video files are MKV or MP4 and none of my "in-house" devices, including two Roku's, transcode.

Thanks for all the input and tips. I will try to do more troubleshooting this weekend.

Maybe a shot in the dark, but I found I was running out of space on the cache for transcoding as my sab downloads were using up a lot of space with a large backlog.

Might be an idea to see where your plex transcoding directory is in your current setup. Can't remember if this is in the unRAID webgui or pms settings

It is defined in the Plex plugin on the UnRaid GUI and it is specifically the temp directory location.  that was the basis of my question above ;-)

Thought that was what you were getting at but it has been a long time since I looked at my unRAID page

Something that comes to mind: Where do you have your temp directory located?

Temp directory is /mnt/cache/appdata/plex/temp

Well I gotta tell ya, your first best bet is to figure out why you are even transcoding to the Roku3.  I have very few sources that need to transcode.  Only the fattest of BD rips forces a transcode (think: Avatar like bitrates).  Just about anything from the scene direct plays, as do most of my full rate BD rips.  That include DTS-HD and TrueDTS which just get stripped, but not transcoded, down to DTS.  And of course even if they were transcoded, audio takes very little cpu.

 

Are you sure you are indeed transcoding to the Roku3?  You can easily check during playback by hitting the down arror button o nthe remote to bring up the info HUD.

 

Another vote for going to 64-bit Beta3 ... even according to the plex devs, 64-bit helps transcoding beyond just more memory because of the larger register space and optimizations in the 64-bit transcoder code.

 

That said, your CPU is rated for about 9000 passmarks so you are right that you should indeed be able to transcode about 6 streams assuming no other load.  But at that point I wonder if you still might start hitting HD and limits if you're trying to serve it all from the same HD and maybe even memory bandwidth [shrug].

Will my other plug ins work if I go to 64 bit? I only use sabnzb, sickbeard and plex

i can't speak to those others personally, but iirc from the forums the answer is, yes there are 64-bit versions available.  that means you need to actually clear out the old 32-bit ones and get the new ones.  but upgrading to 6.0beta also means first bringing the server online with NO plugins first.

Sorry for all the questions but I am not very good at all this learning as I have been going. But here is a screen shot of my plex server playing several things on my home network. One Roku is not transcoding but 2 others are.

Are they all connected through wifi? How reliable is your router?

Your cpu should be fast enough for that. My old dual core sempron can handle 2 transcodes at once

Are they all connected through wifi? How reliable is your router?

 

Your cpu should be fast enough for that. My old dual core sempron can handle 2 transcodes at once

No everything is wired with gigabit switches and routers

I have had this very same issue and it turned out to be because I was transcoding for audio. If your stereo, soundbar or television doesn't support the audio codec being received by roku via Plex it gets transcoded.

Example, my Vizio 60" TV does not support DTS audio, so despite the fact that it is optical cable from TV to sound bar, which does support it, causes plex to transcode it.

There is a log file in Plex you can tail and grep for the detail of transcoding taking place. A "1" means real time direct stream and anything slower is transcoded.

I would dig on plex forums as well. If you're a plex pass member, the gurus there are always helpful. Just like us with unraid.

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and if you are using a Roku, you can press the down button during play and a HUD will popup giving your stream details.

and if you are using a Roku, you can press the down button during play and a HUD will popup giving your stream details.

Thanks!  Did not know that.