Gave those commands a try on my array
Unraid 6.1.3
Motherboard - SSD cache, 1.5TB, 3TB, 5TB, SDD cache
SAS2LP - 1.5TB, 2TB, 2TB, 5TB, 2TB, 3TB
Total 10 drives
Before:
Elapsed time: 8 minutes
Current position: 22.1 GB (0.4 %)
Estimated speed: 44.7 MB/sec
Estimated finish: 1 day, 6 hours, 54 minutes
Disk stats: ~330MB/s
After:
Elapsed time: 10 minutes
Current position: 30.8 GB (0.6 %)
Estimated speed: 108.1 MB/sec
Estimated finish: 12 hours, 46 minutes
Disk stats: ~860MB/s
I say the results look pretty good!
EDIT:
Parity check much further along now and has slowed down a bit.
Elapsed time: 4 hours, 28 minutes
Current position: 1.38 TB (27.6 %)
Estimated speed: 61.7 MB/sec
Estimated finish: 16 hours, 18 minutes
Disk stats: ~480MB/s