Hi!
I was invited to investigate a poor performance of storage system based on adaptec raid card. Storage server consists of 12 6Tb WD RED nasware 3.0 disks. I reconnected 5 of them to my PC through USB-SATA adapter and ran HDD Tune tests (same tests on each drive). And i found out that 4 out of 5 disks have poor write performance (I’ve not tested other disks yet, but it seems to me that all other not tested disks have the same issue):
Serial - read MIN/MAX/AVG (avg access time) in MB/s - write MIN/MAX/AVG (avg access time) MB/s
7SV22 - 33.0/35.4/35.1 (-) - 5.2/5.8/5.7 (18ms)
7S75H - 18.4/35.9/35.0 (16.3ms) - 30.2/34.2/32.6 (5.83ms)
3364C - 33.5/35.2/34.7 (16.3ms) - 5.6/5.8/5.7 (17.6ms)
8032D - 29.8/35.6/33.7 (16.3ms) - 1.2/5.8/4.5 (-)
K986P - 34.8/36.0/35.6 (-) - 5.5/5.8/5.7 (18ms)
I wonder what is the cause of so low write performance around of 4-5 MB/s. I’m considering 2 possible ways how we come here:
- Our company bought already defective disks (what is the possibility to buy many defective disks at once)
- Those drives were used in non native scenario for them (raid workload) and somehow got degradated.
Any help?
Thanks in advance!
