[PVE-User] sparse and compression

Andreas Herrmann andreas at mx20.org
Mon Dec 11 15:47:56 CET 2017


Hi

On 11.12.2017 14:17, Fabian Grünbichler wrote:
> On Mon, Dec 11, 2017 at 01:40:28PM +0100, Miguel González wrote:
>>  Why a virtual disk shows as 60G when originally It was 36 Gb in raw format?
>>
>>  NAME                       USED  AVAIL  REFER  MOUNTPOINT
>>  rpool/data/vm-102-disk-1  60.0G  51.3G  20.9G  -
> 
> wild guess - you are using raidz of some kind? ashift is set to 12 /
> auto-detected?

No! 'zpool list' will show what is used on disk. zfs list is totally
transparent to zpool layout. Have a look at 'zpool get all' for the ashift
setting.

Example for raidz1 (4x 960GB SSDs):
root at foobar:~# zpool list
NAME    SIZE  ALLOC   FREE  EXPANDSZ   FRAG    CAP  DEDUP  HEALTH  ALTROOT
zpool  3.41T   102G  3.31T         -     8%     2%  1.00x  ONLINE  -

root at foobar:~# zfs list
NAME                             USED  AVAIL  REFER  MOUNTPOINT
zpool                            237G  2.17T   140K  /zpool

zpool ALLOC is smaller than zfs USED in this example. Why? Try to unserstand
the difference between 'referenced' and 'used'. My volumes aren't sparse but
discard is used.

Andreas


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