[F5-422 4.1.27] - slow SSD write

[seba22]

Hello,

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

same speed i got on another company ssd (around 50MB/s) with is totally bad for SSD.

for sequential write i would expect at least 200MB/s

I tried doing blkdiscard

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blkdiscard /dev/sde

But no positive effect.

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?

[TMSupport]

Hi, thanks for the reporting. We will test here first and get back to you later.
May I know your installed HDD and SSD model number, and created RAID mode in return?

[seba22]

RAID 5 created from 4 HDD drives (the same model) visible bellow:

SSD actual mounted:

[TMSupport]

As for writing from your computer to the NAS, is it possible that the speed may be related to the performance of the computer?

[TMroy]

And make sure your SSD is at healthy condition.