Help diagnosing a disk performance issue

[ny888]

I have been running unRaid since November of last year and it replaced 2 ReadyNAS NV+ systems.  I have always had issues with one disk and I'm hoping someone can help me figure out why.

 

All drives are WD 3TB Green drives.

 

Parity (sda)

Cache (sdb)

Media share (sdc, sdd) - contains movies and shows under 4 different folders

Backup share (sde) - contains Time Machine backups and backup of a Windows Home Server

 

I am on a iMac running Mountain Lion.  I started using cache_dirs because the Finder was always slow when trying to access Media or Backup.  Since I started using cache_dirs, Media is very quick to respond when I click on it's folder or sub folders in Finder but Backup is still painfully slow to the point where sometimes all I get is the spinning ball and I have to relaunch Finder to get out of it.  I can't undnerstand why that is, both shares are set up the same way.  It doesn't matter whether I'm trying to access thru SMB or AFP.

 

A week ago my switch failed and when I replaced it, my Windows Home Server would no longer start.  Fortunately, the WHS was backed up every night using Robocopy to unRaid so I lost nothing.  On my Backup share is a folder called Snap which is a duplicate of what I had on my WHS - all of our family photos, videos, documents, etc.

 

Since I had the backup on the Backup share and it will take me awhile to replace the WHS with something else, I decide to copy the entire Snap folder on unRaid to my Thunderbolt drive on my iMac.  At first I thought I'd just use Finder and copy the whole folder by Drag-n-Drop but it was painful seeing the Preparing to copy dialog that seemed to be taking forever.  This was on 5/28.  I killed that and instead went to do the copy in Terminal using this command - cp -Rv * /Volumes/"Thunderbolt Duo"/Snap

 

This process started on 5/28 at 7:18pm.  Since I used the -v option I could see that the process was again painfully slow.  By the time I went to bed, very few folders and files had been copied.  In the morning I checked and noticed it timed out all over the place on the morning of 5/29.  Without doing anything, I decided to just issue the cp command again because I had to go on a business trip.  This started on 5/29 at 5:50am and immediately I could see it was flying through the folders and files !

 

I've attached the syslog hoping someone can help me solve why this Backup disk has always given me trouble in Finder and why the same cp command at one time was slow and timed out and then worked as I had hoped after I had done nothing to change the environment.

 

syslog-2013-05-31.txt.zip

[ny888]

Since these backups are contained within just 1 disk, could it be a problem that I have split level set to 2 ?  What hapens if I change the split level while the array is up?

[Joe L.]

Since these backups are contained within just 1 disk, could it be a problem that I have split level set to 2 ?  What hapens if I change the split level while the array is up?

you can change the split level at any time.  It only affects future writes to the array.

[ny888]

I did not have disk share turned on and turned it on - definitely improved response time in the Finder.  Not great, but much better.  Why is that?

 

Meant to say performance in terms of drilling into folders is quicker accessing the dish share as opposed to the user share.

[dgaschk]

Try the latest release.