Mirror seeing half the write IOPS on one disk than the other, is this normal?
Mirror seeing half the write IOPS on one disk than the other, is this normal?
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Mirror seeing half the write IOPS on one disk than the other, is this normal?
I'm syncoiding from my normal RAIDz2 to a backup mirror made of 2 disks. I looked at zpool iostat and I noticed that one of the disks consistently shows less than half the write IOPS of the other:
capacity operations bandwidth
pool alloc free read write read write
------------------------------------ ----- ----- ----- ----- ----- -----
storage-volume-backup 5.03T 11.3T 0 867 0 330M
mirror-0 5.03T 11.3T 0 867 0 330M
wwn-0x5000c500e8736faf - - 0 212 0 164M
wwn-0x5000c500e8737337 - - 0 654 0 165M
This is also evident in iostat:
f/s f_await aqu-sz %util Device
0.00 0.00 3.48 46.2% sda
0.00 0.00 8.10 99.7% sdb
The difference is also evident in the temperatures of the disks. The busier disk is 4 degrees warmer than the other. The disks are identical on paper and bought at the same time.
Is this behaviour expected?