Plugins slow down CIFS transfers and even crash FreeNAS

[Johannez]

After moving my jails to a pair of mirrored SSD's on my FreeNAS 1 server i encountered problems with some plugins.
At first i thought it would be the controller of my C2750D4I motherboard cause i placed both SSD's on the 4 ports Marvell controller which is known for its problems but this seemed not the case. After more investigation i have to say i did not encountered controller problems yet with the C2750D4I.

To move the jails i used this guide:
https://forums.freenas.org/index.ph...-volume-to-new-ssd-volume.42105/#post-271740]

The problems i encountered after the move where:
Plex Mediaserver crashing after 30 min or so and the storage window in the FreeNAS UI would not load at all (blank window). Only a restart of the FreeNAS server would fix it.
Sabnzbd slowing down all transfers to different CIFS shares.

I did a fresh install of FreeNAS 9.10 and placed back my config file and changed the SSD's to another controller, this did not help the problems remained.

I still wanted to move Plex to my other server so for now the problem of a crashing Plex and FreeNAS i could avoid.
Today i wanted to start fresh with the jails on my first server but to do that i first wanted to install the plugins and jails i used on it on the other server which where not possible due to another new problem:
https://forums.freenas.org/index.php?threads/unable-to-find-template-cant-install-new-plugins.46205/
So starting fresh is not an option now.

The second problem (the one i hope to fix now), slow transfer speeds on CIFS shares when Sabnzbd is in use, normally i would have write speeds of 95/100 mb sec to FreeNAS (writing to another volume, 6xWD Red RaidZ2 instead of the SSD's) but when i download with Sabnzbd (and not even repair or verify, just download) with only 10mb /sec (throttled) my write speeds to the CIFS share drop down to 6/20 mb/sec.
the moment i pause the downloads the write speeds go up again and stay up.

I never seen this before i switched to the SSD's and did the fresh install of FreeNAS.

Any help in solving this strange problem?
If i can fix the other problem i can test more by installing plugins and other jails again but i am very limited atm.

 

[Joshua Parker Ruehlig]

One thing I thought of would be to increase sabnzbd's 'Article Cache Limit' which would increase how much memory sabnzbd uses and lower how much random IO it consumes.

 

[Johannez]

Thank you for your suggestion, i had it set to 150M.
Just now i tried it with different settings and both did not effect the slow speeds at all.
I tried -1 for no limit, and 0 for no memory use.

It feels like the plugin or jail uses/reserves more resources then it should.

Here are some statistics of download and write speed i see at this moment:

Code:

Sabnzbd Download speed (on SSD):             avarage write speed to another volume:
0 (pauzed)                                                           95 mb/sec
18 mb/sec                                                              6 mb/sec
10 mb/sec                                                            15 mb/sec
  5 mb/sec                                                            35 mb/sec
  1 mb/sec                                                             70 mb/sec
These are rough estimates.

The write speeds really changes a lot, seems that with every write action Sabnzbd does on the SSD's disks the write actions on the other volume slows down with huge amounts.
If this also effected Plex i can understand why Plex crashed and FreeNAS with it.

Writing data simultaneous to both shares (without a plugin) does not cause any problems, the transfer speed get cut in half for both transfers.

 

[Joshua Parker Ruehlig]

hmm maybe you should look at your available RAM?

 

[Johannez]

This server has 32g of RAM but almost everything will be used/reserved by FreeNAS. I haven't seen it different.

 

[Joshua Parker Ruehlig]

I'm not sure, I think you should do benchmarking of the random IO for that SSD, sounds like it's causing a bottleneck of some sort

 

[Johannez]

It's a pair of ssd's in mirror, both brand new but this should not make much difference if they would be bad. I could test them, I don't know how however in FreeNAS.

But let's say the ssd's are faulty how can this effect another volume in write speeds? When I am writing only 10mb a sec to the ssd's?

 

[Joshua Parker Ruehlig]

i don't know, and don't plan to speculate more. goodluck

 

[Johannez]

Thank you anyway for helping out.