- Minor
I have 9 disks for zfs format data disk and 2 parity disk for unraid array.When I read data from 9 data disks simultaneously through /mnt/diskx, the overall throughput is very low, only 300M/s, slightly higher than the throughput of a single disk (260M/s). At the same time, I can see that my 32-core 7d12 CPU is almost fully loaded in the background. By using the "top" command, I can see that processes like unraidd1 and unraidd2 are consuming a significant amount of CPU.
I have confirmed that my hard disk bandwidth is sufficient to support all my disks being fully loaded for reading simultaneously. During parity check, all 11 hard disks can operate at speeds above 250M/s.
some test:
3disks
9disks
It is highly likely that Unraid has assigned a separate kernel thread for each disk to handle IO requests,but miuse spin locks during those thread(more disk,slow thorughput,but higher cpu usage).