[PVE-User] ZFS 'zpool trim'?

[PVE-User] ZFS 'zpool trim'?

[Marco Gaiarin]

I've tried a 'zpool trim' on a SSD pool in one of my server, after
searching about and finding:

	https://openzfs.org/wiki/Features#TRIM_Support

Seems to work as expected (at least: print in logs:

	Nov  4 18:12:38 ino zed: eid=68 class=trim_start pool_guid=0x76DD565E9F8A86A8 vdev_path=/dev/disk/by-id/ata-KINGSTON_SEDC500M480G_50026B7683586349-part3 vdev_state=ONLINE
	Nov  4 18:12:38 ino zed: eid=69 class=history_event pool_guid=0x76DD565E9F8A86A8  
	Nov  4 18:13:37 ino zed: eid=70 class=trim_finish pool_guid=0x76DD565E9F8A86A8 vdev_path=/dev/disk/by-id/ata-KINGSTON_SEDC500M480G_50026B7683586349-part3 vdev_state=ONLINE
	Nov  4 18:13:37 ino zed: eid=71 class=history_event pool_guid=0x76DD565E9F8A86A8  

and don't destroy my disk. ;-)


But i've tried to look into PVE wiki, or in PVE ZFS packages for some
docs, or scripts, and found nothing.


There's some drawbacks of trimming ZFS pools in PVE, and so it is not
enabled by default?
Or simply there's no way to determine a ZFS pool composed of SSD disks,
and so it is up to the sysadmin to setup a script for trimming?


Thanks.

-- 
dott. Marco Gaiarin				        GNUPG Key ID: 240A3D66
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	(cf 00307430132, categoria ONLUS oppure RICERCA SANITARIA)

Re: [PVE-User] ZFS 'zpool trim'?

[Mark Schouten]

On Wed, Nov 04, 2020 at 05:28:06PM +0000, Mark Adams via pve-user wrote:
> Can't comment on why it's not enabled by default (or a checkbox maybe when
> creating through the gui?) but just enable autotrim on your ssd pools.
> 
> zpool set autotrim=on POOLNAME

I did this, at first. But then disabled it becuase it slowed down my
storage quite a bit. Might be specific to my setup, but the
trim-kernel-thread took quite some IO according to iotop.


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Re: [PVE-User] ZFS 'zpool trim'?

[Marco Gaiarin]

Mandi! Mark Schouten
  In chel di` si favelave...

> > zpool set autotrim=on POOLNAME

> I did this, at first. But then disabled it becuase it slowed down my
> storage quite a bit. Might be specific to my setup, but the
> trim-kernel-thread took quite some IO according to iotop.

Exactly, i've read also that, that also 'match' with what 'normally' i
know on trim: apart some specific usage case, doing an automatic trim
could be a slowdown, and is preferable to schedule a
daily/weekly/monthly task, based on usage profiles, to do a trim.

It seems strane to me that debian/Proxmox does not have a 'framework'
(apart /etc/cron.d/zfsutils-linux; i meant something like a predefined
systemd unit) for that.


A crontab will suffices. ;-)

-- 
dott. Marco Gaiarin				        GNUPG Key ID: 240A3D66
  Associazione ``La Nostra Famiglia''          http://www.lanostrafamiglia.it/
  Polo FVG   -   Via della Bontà, 7 - 33078   -   San Vito al Tagliamento (PN)
  marco.gaiarin(at)lanostrafamiglia.it   t +39-0434-842711   f +39-0434-842797

		Dona il 5 PER MILLE a LA NOSTRA FAMIGLIA!
      http://www.lanostrafamiglia.it/index.php/it/sostienici/5x1000
	(cf 00307430132, categoria ONLUS oppure RICERCA SANITARIA)