is it safe to disable atime enable relatime for all datastores with qcow2/raw/vmdk/vzdump files ?

[RolandK]

hello,

as i found that atime can cause pathological slowness ( https://forum.proxmox.com/threads/w...source-disks-when-moving-virtual-disk.123639/ ) , i'd like to set atime=on and relatime=on on all my datastores and also on the backup target where vzdumps being written to.

i know that relatime is being ok for pbs.

is this safe to do for vm and vzdump datastores/directories ?

regards

 

[RolandK]

anybody here using atime=on or atime/relatime=on with vm or vzdump datastores in production ?

 

[janssensm]

Hi, I was wondering too as I saw some scattered discussions on using atime and relatime on zfs datasets. And I assumed this thread is about zfs as your linked post is about zfs datasets .

My pve host (pve-manager/7.4-3/9002ab8a) was installed prior to pve 7.x and zfs rpool dataset has defaults from install time:
relatime=off, atime=off
The other pools were created manually via cli, they got other defaults (from zfs I assume):
relatime=off, atime=on

There is this commit for the pve installer:
https://git.proxmox.com/?p=pve-installer.git;a=commit;h=9bc6376d6aab098134c0dec3ca6567dfb964267d

zfs create: default to relatime
like other FSs do already.

So I did a test install from latest proxmox-ve_7.4-1.iso and installed it with root on a zfs mirror pool via the guided setup.
It end up with zfs rpool dataset:
relatime=on, atime=on
So, I think this would answer your question I guess, as the default pve install has these settings.
Manually created zfs pools still default to relatime=off, atime=on.

Maybe proxmox staff could advise what defaults currently should be used (for all pools) and/or maybe hint for that in the admin docs.

 

[fabian]

yeah, PVE itself doesn't really care about atime anywhere (important) AFAIK.

 

[Thibaultmol]

yeah, PVE itself doesn't really care about atime anywhere (important) AFAIK.

I'm wondering then: is there a reason why it's not either disabled by default or easily changeable in the UI

Because anyone who is using ZFS on SSD's as their proxmox boot drive would probably want atime to be disabled right? (to extend it's life)

 

[fabian]

relatime is already the default?

 

[Thibaultmol]

relatime is already the default?

apologies, misread the thread. thank you