So I have noticed my read write speeds have been really slow recently.

 

Parity checks are causing my webgui to hang and as far as i can tell average less than 2MB/s.  Transferring files to the tower can be as slow as 2-3mbps with no other traffic.  Transfers between directories on the tower are also slow.

 

Here is my setup:

 

2x WD Caviar Red 3TB

1x Seagate Barracuda 3TB

1x WD Caviar Red 2TB

1x Samsung 840 120GB Cache Drive

1x WD Caviar Red 3TB Parity

 

Intel core i3 2nd gen

 

running Unraid 5.0.5 w/Plex, Sickbeard, Sabnzbd, and couchpotato.

 

I would attach a system log, but i cannot seem to zip it down to a small enough file to upload (given the 192kb limit)

 

Thanks for the help in advance!

Test in safe-mode. Need a syslog to help. Post it on google or Dropbox.

So now running the parity check in safe mode and I'm getting closer to what I would expect speed wise (70-100mbps). 

 

I guess my next steps would be to remove the plugins and readd them one by one to find out where the culprit is?

 

 

Perform a dichotomic search starting with half of the addons.  If multiple addons in combination cause the problem additional tests will be required.

Ok I appreciate the help, but I have absolutely no idea what that means.  If you could just direct me to some instructions I'd be grateful.

 

Thanks!

Use a process of elimination by loading half of the add-ons. Repeat testing on the half that contains the culprit by testing half of those. Repeat until culprit is identified.  http://xlinux.nist.gov/dads//HTML/dichotomic.html

So it appears that the Dynamix webui plugin is causing the issue.  I decided to go the clean route and simply start installing one by one before doing the type of diagnostic you all suggested, and low and behold on the first plugin (Dynamix Webgui 2.2.10) is what seems to cause the slow parity check speeds.  Actually not sure if it's the speeds or the gui simply not responding. 

 

Any advice or suggested alternatives? 

Do you have the Dynamix Web GUI open when doing the parity check?  If you have the GUI open and have the option for automatic updating set then that is know to cause a major slowdown in the parity check as it will be continually accessing the disks for their status.