* [PVE-User] ZFS Disk Usage unexpected high
@ 2021-04-05 8:22 Konold, Martin
2021-04-05 9:54 ` Yanni M.
2021-04-06 7:41 ` Maximilian Hill
0 siblings, 2 replies; 3+ messages in thread
From: Konold, Martin @ 2021-04-05 8:22 UTC (permalink / raw)
To: Proxmox VE user list
Hi,
I set up a single VM which currently used 15TB of data.
/dev/sdb is technically a ZFS volume on the Proxmox Host.
[root@vm ~]# df -h /data
Filesystem Size Used Avail Use% Mounted on
/dev/sdb 40T 15T 25T 37% /data
[root@vm ~]# du -s /data/
14874345100 /data/
[root@host /]# zfs list zfs01/PVE-BE/vm-1-disk-1
NAME USED AVAIL REFER MOUNTPOINT
zfs01/PVE-BE/vm-1-disk-1 31.5T 5.82T 31.5T -
Why is the usage on the host about twice as large as within the vm?
(Yes, I have given fstrim and discard a try).
--
Regards
ppa. Martin Konold
--
Martin Konold - Prokurist, CTO
KONSEC GmbH - make things real
Amtsgericht Stuttgart, HRB 23690
Geschäftsführer: Andreas Mack
Im Köller 3, 70794 Filderstadt, Germany
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PVE-User] ZFS Disk Usage unexpected high
2021-04-05 8:22 [PVE-User] ZFS Disk Usage unexpected high Konold, Martin
@ 2021-04-05 9:54 ` Yanni M.
2021-04-06 7:41 ` Maximilian Hill
1 sibling, 0 replies; 3+ messages in thread
From: Yanni M. @ 2021-04-05 9:54 UTC (permalink / raw)
To: Proxmox VE user list
This is a common issue on raidz based pools. Assuming 4k sectors
(ashift=12) and zvol with 8K volblocksize, each 8K (2-sector) block uses a
single sector (4k) of parity. So 15TB of 8KB blocks (default
volblocksize=8k) takes up at least 22.5TB space on disk (including parity).
You will use less parity by increasing the volblock size (e.g.
volblocksize=32k, or the default recordsize=128k for filesystems) in
exchange of a possible lower performance. Another solution would be using a
pool of striped mirrors (RAID10). This problem does not exist in such pools
(as there are no parity blocks used).
On Mon, 5 Apr 2021 at 09:23, Konold, Martin <martin.konold@konsec.com>
wrote:
>
> Hi,
>
> I set up a single VM which currently used 15TB of data.
> /dev/sdb is technically a ZFS volume on the Proxmox Host.
>
> [root@vm ~]# df -h /data
> Filesystem Size Used Avail Use% Mounted on
> /dev/sdb 40T 15T 25T 37% /data
> [root@vm ~]# du -s /data/
> 14874345100 /data/
>
> [root@host /]# zfs list zfs01/PVE-BE/vm-1-disk-1
> NAME USED AVAIL REFER MOUNTPOINT
> zfs01/PVE-BE/vm-1-disk-1 31.5T 5.82T 31.5T -
>
> Why is the usage on the host about twice as large as within the vm?
> (Yes, I have given fstrim and discard a try).
>
> --
> Regards
> ppa. Martin Konold
>
> --
> Martin Konold - Prokurist, CTO
> KONSEC GmbH - make things real
> Amtsgericht Stuttgart, HRB 23690
> Geschäftsführer: Andreas Mack
> Im Köller 3, 70794 Filderstadt, Germany
> <https://www.google.com/maps/search/Im+K%C3%B6ller+3,+70794+Filderstadt,+Germany?entry=gmail&source=g>
>
> _______________________________________________
> pve-user mailing list
> pve-user@lists.proxmox.com
> https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-user
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PVE-User] ZFS Disk Usage unexpected high
2021-04-05 8:22 [PVE-User] ZFS Disk Usage unexpected high Konold, Martin
2021-04-05 9:54 ` Yanni M.
@ 2021-04-06 7:41 ` Maximilian Hill
1 sibling, 0 replies; 3+ messages in thread
From: Maximilian Hill @ 2021-04-06 7:41 UTC (permalink / raw)
To: Proxmox VE user list
[-- Attachment #1: Type: text/plain, Size: 935 bytes --]
Hi,
I got the same issue with different RAID-Z setups lately.
We worked around it, but I don't want to go into detail abaout that
before I know. why that happened.
Regards
Maximilian Hill
On Mon, Apr 05, 2021 at 10:22:56AM +0200, Konold, Martin wrote:
>
> Hi,
>
> I set up a single VM which currently used 15TB of data.
> /dev/sdb is technically a ZFS volume on the Proxmox Host.
>
> [root@vm ~]# df -h /data
> Filesystem Size Used Avail Use% Mounted on
> /dev/sdb 40T 15T 25T 37% /data
> [root@vm ~]# du -s /data/
> 14874345100 /data/
>
> [root@host /]# zfs list zfs01/PVE-BE/vm-1-disk-1
> NAME USED AVAIL REFER MOUNTPOINT
> zfs01/PVE-BE/vm-1-disk-1 31.5T 5.82T 31.5T -
>
> Why is the usage on the host about twice as large as within the vm?
> (Yes, I have given fstrim and discard a try).
>
> --
> Regards
> ppa. Martin Konold
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-04-06 7:42 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-04-05 8:22 [PVE-User] ZFS Disk Usage unexpected high Konold, Martin
2021-04-05 9:54 ` Yanni M.
2021-04-06 7:41 ` Maximilian Hill
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.
Service provided by Proxmox Server Solutions GmbH | Privacy | Legal