I have a supermicro 847 case with Supermicro X11DPH-T main board.  I have approximately 26 drive bays in use using the AOC-S3008L-L8e card.  

 

My biggest drives are 20TB - with 2 20TB parity drives, several 20TB data drives along with 10 or so 18TB drives and the smallest drives in my system are 8TB.  (356TB total space)

 

I just did a New Config and Parity Sync that took nearly 4 days!  The average speed was around 58MB/Sec but periods where it was running at 86-88MB/Sec.  

 

On my old server with as many drives (but smaller) - I remember speeds around 125MB/Sec.  

 

What could the issue be?  Why is everything running so slowly?  Do I have too many drives?  Is my controller card ok?   

 

I bought the system off ebay - here is the original link - https://www.ebay.com/itm/134240978762

 

I run ESXI Vmware and Unraid is a VM.   Maybe there is an issue somewhere in there?

Appreciate any help.  

Thank you

Have you checked for controller bottleneck with the Diskspeed docker ?

Your diagnostics might show something interesting also.

Attached are my diagnostics.  I will start running the diskspeed app now.  Just can't figure out why things don't run much faster than I think they should.  I thought I got the most robust system possible for my unraid setup.  4 days to do a parity check is too long.

tower-diagnostics-20240702-2234.zip

Make sure you run the controller test, not just the disks 

Here are the results from my controller test.

 

 

Controller Speed Test.pdf

Disks 23 to 26 as well as your cache are significantly slower.

Is there something specific / different for those drives ?

These disks are bottlenecking when accessed simultaneously:

 

 

And looking and the diags, they appear to be connected to a second expander, please detail how the disk are connected in the enclosure(s)

I noticed the same thing too.   At first I thought - "oh these are the drives located on the back side of my Supermicro SC847 server case."   But the disk numbers from speeddisk do not correspond with the Drive numbers of my array.  

I am trying to figure out my Drive Number vs Port Number vs Disk Number in Speed Disk.  I don't think they are the same.