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SSD pool - please help me understand trim behavior

Western Digital Drives - The Preferred Drives of FreeNAS and TrueNAS CORE


Jan 18, 2020

Can someone clarify my confusion related to "trim" and freenas zfs pool on SSD.

I found this thread:

after looking why stats for my SSD shows big red "delete" counters (comparing to "write" and "read")

On this pool I keep zvols for bhyve VM's (at time of above capture there was only one Windows 10 running).

I'm using

PlatformIntel(R) Core(TM) i5-2500T CPU @ 2.30GHz

Flowing related post, I have also check zfs "trim" stats:

# sysctl -a |grep _trim
kstat.zfs.misc.zio_trim.failed: 0
kstat.zfs.misc.zio_trim.unsupported: 15266
kstat.zfs.misc.zio_trim.success: 10901023
kstat.zfs.misc.zio_trim.bytes: 1304282636288

Here "success" and "bytes" values are constantly growing.

I'm worried that my SSD will suffer - am I wrong?

Or this is strictly normal behavior, and correctly working system with SSD will always show "delete's" on monitoring and "trim" on sysctl?

I was not able to find details about how to read "stat.zfs.misc.zio_trim" properly.

Anyone can explain?

Thanks to anyone reading up to this point :)