diskdiddler
Wizard
- Joined
- Jul 9, 2014
- Messages
- 2,377
I am messing around with ZSTD compression for fun and I'm moving ZVOLs around my SSDS in my system.
I have 3 VMs using 3 ZVOLs with maximum compression. They're fantastic - only 21GB for them. (before snapshots)
I am creating 3 'blank' ZVOLS to migrate them to another SSD, the 3 blank ZVOLS I'm creating the same way I created the current ones they're using.
When I do so, instantly, all drive space is allocated. I'm not ticking 'sparse' or 'force size'.
The resulting zvols are using ALL allocated space, immediately, before even ZFS send / recving data to them.
To be clear the ones at the bottom ARE VM ZVOLS, running and live, consuming a total of 21.9GB. The disks are /allocated/ 10/10/80GB - but they're consuming 21.9GB
Why, when I go to create the top ones, does it instantly allocate 101.5GB and when I send / recv into those ZVOLs they get even larger still?
I'm clearly missing something here.
See screenshot:
I 100,000% created the bottom disks, only yesterday, using the same method and they consumed only 21GB.
I have 3 VMs using 3 ZVOLs with maximum compression. They're fantastic - only 21GB for them. (before snapshots)
I am creating 3 'blank' ZVOLS to migrate them to another SSD, the 3 blank ZVOLS I'm creating the same way I created the current ones they're using.
When I do so, instantly, all drive space is allocated. I'm not ticking 'sparse' or 'force size'.
The resulting zvols are using ALL allocated space, immediately, before even ZFS send / recving data to them.
To be clear the ones at the bottom ARE VM ZVOLS, running and live, consuming a total of 21.9GB. The disks are /allocated/ 10/10/80GB - but they're consuming 21.9GB
Why, when I go to create the top ones, does it instantly allocate 101.5GB and when I send / recv into those ZVOLs they get even larger still?
I'm clearly missing something here.
See screenshot:

I 100,000% created the bottom disks, only yesterday, using the same method and they consumed only 21GB.