Parity check began recently but its going way slower than usual.  averaging around 15MB/s rather than the 150+MB/s it has done in the past.  I see no errors in the logs, VM Service is turned off.  I checked the disk controller, its attached at x8 and all the drives seem to be capable of a decent speed.  Diags attached.

 

tower-diagnostics-20250204-1200.zip

Looks as if you have some writing going on to some disks (4 and 9).   Any writing will badly degrade the parity check speed while they are running in parallel.

hmm, I have disabled Docker and its still slow.  how can I check whats writing to disk?

 

Looking at the htop I/O tab, it only shows /usr/libexec/unraid/shfs as reading/writing to disk

8 minutes ago, mattekure said:

Looking at the htop I/O tab, it only shows /usr/libexec/unraid/shfs as reading/writing to disk

That is the process that handles Use Shares so you do not want it to be very active during a parity check.

37 minutes ago, mattekure said:

I have disabled Docker and its still slow.

None of your Docker/VM related shares are on the array anyway.

 

What else is reading/writing the array?

How do you have Mover scheduled?

I thought Mover was disabled during parity checks, but it appears to be running for some reason.  

ok, after manually stopping mover and turning off docker and vm.  it appears to be running at a normal speed of 200MB/s now.  thanks all!

5 hours ago, mattekure said:

ok, after manually stopping mover and turning off docker and vm.  it appears to be running at a normal speed of 200MB/s now.  thanks all!

If you have the Parity Check Tuning plugin installed you can set it work the other way - automatically pause the array operation while mover is running and then resuming when mover completes.