Horrific I/O Performance on NAS w/ SMR drives

[flopsy]

So I have been debugging terrible performance issues on this 8x8TB NAS with all drives being SMR :(

As expected, performance is horrific. There is a nextcloud vm instance sitting on this NAS that takes tens of seconds to login. I have checked network performance via iperf, and it is as expected.

Just listing the files on the zfs volume takes multiple seconds.

root@freenas:~ # zpool iostat -v
capacity operations bandwidth
pool alloc free read write read write
-------------------------------------------------- ----- ----- ----- ----- ----- -----
atlas 7.24T 30.8T 5 59 62.4K 805K
raidz2 7.24T 30.8T 5 59 62.4K 805K
gptid/8f6f62db-6627-11e8-aba7-ac1f6b68dfca.eli - - 0 8 8.90K 115K
gptid/9044febf-6627-11e8-aba7-ac1f6b68dfca.eli - - 0 8 8.95K 115K
gptid/9132c72a-6627-11e8-aba7-ac1f6b68dfca.eli - - 0 8 8.93K 115K
gptid/92154205-6627-11e8-aba7-ac1f6b68dfca.eli - - 0 8 8.93K 115K
gptid/9304e67a-6627-11e8-aba7-ac1f6b68dfca.eli - - 0 8 8.97K 115K
gptid/93f2f7a5-6627-11e8-aba7-ac1f6b68dfca.eli - - 0 8 8.75K 115K
gptid/94cfe773-6627-11e8-aba7-ac1f6b68dfca.eli - - 0 8 8.95K 115K
-------------------------------------------------- ----- ----- ----- ----- ----- -----
freenas-boot 5.74G 232G 1 0 101K 458
nvd0p2 5.74G 232G 1 0 101K 458
-------------------------------------------------- ----- ----- ----- ----- ----- -----

I have been reading this post: https://www.truenas.com/community/threads/update-wd-red-smr-drive-compatibility-with-zfs.88413/

And tried some of the suggestions there, specifically:

* Trim is disabled:

root@freenas:~ # zpool get autotrim
NAME PROPERTY VALUE SOURCE
atlas autotrim off default
freenas-boot autotrim off default

* set vfs.zfs.spa_allocators: 1

But performance is still terrible.

Replacing these drivers is not an option in the near future, is there anything else I can do/check to improve performance? The utilization of these drives is likely to stay low in the near future as well, max 33% expected utilization.

 

[jgreco]

You're running Nextcloud as a VM on a RAIDZ2 using SMR drives?

Easy fix: blow away the RAIDZ2 and go to mirrors. This probably won't make it magically fast, but it should help somewhat.

https://www.truenas.com/community/threads/the-path-to-success-for-block-storage.81165/

Please do take the time to read that and take it to heart.

 

[Patrick M. Hausen]

Second, why are you running Nextcloud in a VM? You can run it just fine in a jail without all the block storage overhead. Just don't use the plugin