Sporadic Slow Read Speed

[jas0r]

Hi

 

I have had unraid running for several years flawlessly. I have just migrated my drives to a new system that has a lot more power for running VM's. Since moving I am getting some really up and down read speeds. I am talking 1 - 3 mb/sec slow when copying files between drives in Midnight Commander. It really frustrating as a file goes slow then later it copies across at 100 mb/sec.

 

The main file system changes are I changed the parity from a 2T to a 4T and added a SSD cache. Physical system wise its all new hardware. 

 

I have run diskspeed.sh and get between 76 mb/sec and 131 mb/sec for my main drives (500mb/sec for cache) so I dont think the drives are the issue.

 

Does anyone have any ideas? 

jas0r-server-diagnostics-20170326-0846.zip

Edited March 26, 2017 by jas0r
Added diagnostics

[jas0r]

Here are a couple examples from MC. It seems when copying from user share its always about 1mb/sec or less but when copying from the disk mnt point it is either 3 mb/sec or other times its at 100 mb/sec

 

There dont seem to be any errors showing for the drives 

[Squid]

All writes wind up getting cached in memory once the cache fills up, then it begins to dump the cache to the destination while continuing to refill the cache.  You get to a point where the cache has to be completely empty for the copy to continue.

 

On every copy of large files, what's important is the average speed.  That's what you need to base whether or not there's a problem on...  

 

Also, using the cache drive as a destination might have its own caveats.  VM's, and appdata for dockers apps could be utilizing all the available bandwidth on the disk.  Garbage collection on the SSD might be taking place.  Always install Dynamix SSD trim and have it run daily

 

Edited March 26, 2017 by Squid

[jas0r]

Hi

I have done some more testing and getting really weird results. I have a Supermicro X10DRL-i motherboard. It mainly seems to be one drive (disk 1) and only certian files, on reboot it will copy in Midnight Commander from user share to usb drive at 70 MB/sec. After 5 mins after reboot its down to 30MB/s and then after 10 mins it averages 1MB/s

Other files copy at 70MB/s all the time.

There are no errors on the drive. Should I look at replacing the drive as its making watching this media problematic? 

I have left all VM's off during these test but Docker is still running but it is 100% run off the cache drive.

Edited April 8, 2017 by jas0r