Virtual Disks Stealing More Space Than Allocated *Help*

[jancell]

Hardware,
Dell R710
PERC H200 (IT Mode)
4x WD80EFAX-68KNBN0 (WD 8TB Red)
RaidZ1 (Pool Size = 29.11 TiB under Datacenter/node/Disks/ZFS/"name-of-pool")

I have a VM installed (Xpenology) that I'm trying to assign most of the pool to however I'm running into an issue where when creating the Virtual Disk(s) it takes way more than it should, I assume, from the pool. For example if I create a 7TB (7168Gib) disk it will take 10.4TiB from the pool. When I create any virtual disk, the pool size shows as only 20.49TiB available. Right now the maximum size virtual disk I can create is 14120GiB for a total of only 13.8TB usable. If I understand ZFS correctly, and I'm sure I don't, I should get at least 19TB+ under this configuration after factoring in the 20% free space limit.

Any pointers, tips or tricks would be greatly appreciated. Thanks for your time!

 

[H4R0]

Increase the vdev block size.

https://docs.google.com/spreadsheet...jHv6CGVElrPqTA0w_ZY/edit?pli=1#gid=2126998674

 

[jancell]

Increase the vdev block size.

https://docs.google.com/spreadsheet...jHv6CGVElrPqTA0w_ZY/edit?pli=1#gid=2126998674

I'm not at all familiar with ZFS but do I understand correctly that the ashift should be set to 9 then?

 

[H4R0]

I'm not at all familiar with ZFS but do I understand correctly that the ashift should be set to 9 then?

No keep ashift to 12.

Set Datacenter -> Storage -> RaidZ1 Pool -> Block Size: 64kb and recreate your vm disk

 

[jancell]

No keep ashift to 12.

Set Datacenter -> Storage -> RaidZ1 Pool -> Block Size: 64kb and recreate your vm disk

You're a god send, thank you! With this setting my usable storage jumped up to 20.4TB. I'm about 1TB shy of where I was when these drives were in a Raid 5 array. If you know the answer as to why that is or if that's expected in my hardware scenario and are willing to share, I'd love to hear it. Either way I'm super grateful for your answer so thank you!

 

[fabian]

read https://pve.proxmox.com/pve-docs/pve-admin-guide.html#chapter_zfs , especially the "ZFS RAID Level Considerations"

 

[H4R0]

You're a god send, thank you! With this setting my usable storage jumped up to 20.4TB. I'm about 1TB shy of where I was when these drives were in a Raid 5 array. If you know the answer as to why that is or if that's expected in my hardware scenario and are willing to share, I'd love to hear it. Either way I'm super grateful for your answer so thank you!

zfs has additional overhead for metadata, checksums, padding etc. thus you get less space then with your traditional raid.