I recently replaced the power cable to a drive that was having errors, as well as added a new drive.
After replacing the power cable, I rebuilt the parity which seemed to be at normal speed. The new drive was also set up at a normal speed. I also updated to the latest version of Unraid around this time.
Today, the regularly scheduled parity check is going extremely slow, anywhere from 2-8MB/s which would take about 3-6 days, where this typically took about 8 hours (with one less drive in the array).
Attached are my diagnostics as well as a DiskSpeed test. I had to pause the parity check otherwise I wasn't able to get the diagnostics without it hanging.
Disk 1 seems to be reading a bit slower than the other drives, but nothing crazy. I am seeing some SMART errors for Disk 1 though which are new.
megatron-diagnostics-20221219-1510.zip