Recently while testing I decided add SSD drive as cache for my F5-422 - (HDD TRAY 5).
After enabling cache i noticed that my performance on writing to NAS went down.
I start trying to diagnose what can be wrong. I replace SSD drive for another vendor but still no luck.
I SSH to TOS and perform write test to SSD directly
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dd if=/dev/zero of=/dev/sde
dd: writing to '/dev/sde': No space left on device
468862129+0 records in
468862128+0 records out
240057409536 bytes (240 GB, 224 GiB) copied, 4631.99 s, 51.8 MB/s
for sequential write i would expect at least 200MB/s
I tried doing blkdiscard
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blkdiscard /dev/sde
I expect maybe something is bad with hardware but read test prove that sata interface it's working fine.
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dd if=/dev/sde of=/dev/null
468862128+0 records in
468862128+0 records out
240057409536 bytes (240 GB, 224 GiB) copied, 585.658 s, 410 MB/s
410MB read 0 that is totally fine.
Have You got any idea what might be wrong?