[SOLVED] unable to create VM: 'volblocksize' must be power of 2 from 512B to 16M

jamesP

New Member
Feb 7, 2025
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I appear to have broken something .. have several vms set up already, went to add a hard drive today and got an error, now getting the same error when I try to create a new one too ...

Code:
TASK ERROR: unable to create VM 104 - zfs error: cannot create 'rpool/vmdata/vm-104-disk-0': 'volblocksize' must be power of 2 from 512B to 16M

I can't see anything weird looking at my the what's already there, I mean 16K is a power of 2 ... I suspect if I knew where the ''non-power of 2" value even was, I would be able to track it down and fix it, but the task isn't giving anything away

Code:
TYPE        NAME                        AVAIL   USED  USEDSNAP  USEDDS  USEDREFRESERV  USEDCHILD  VOLSIZE  VOLMODE  OBJSETID  XATTR  MOUNTPOINT
filesystem  rpool                       1.03T   873G        0B    120K             0B       873G        -  default        54  sa     /rpool
filesystem  rpool/ROOT                  1.03T  49.8G        0B    107K             0B      49.8G        -  default        68  sa     /rpool/ROOT
filesystem  rpool/ROOT/pve-1            1.03T  49.8G        0B   49.8G             0B         0B        -  default        76  sa     /
filesystem  rpool/backup_zfs            1.03T   109K        0B    109K             0B         0B        -  default      6228  sa     /mnt/pve/backup_zfs
filesystem  rpool/data                  1.03T   184K        0B    109K             0B      74.6K        -  default       515  sa     /rpool/data
volume      rpool/data/vm-104-disk-0    1.03T  74.6K        0B   74.6K             0B         0B      32G  default       278  -      -
filesystem  rpool/var-lib-vz            1.03T   157K        0B    157K             0B         0B        -  default       643  sa     /var/lib/vz
filesystem  rpool/vmdata                1.03T   410G        0B    109K             0B       410G        -  default     25886  sa     /rpool/vmdata
volume      rpool/vmdata/vm-100-disk-0  1.03T  18.2G     1.48G   16.7G             0B         0B      32G  default       166  -      -
volume      rpool/vmdata/vm-101-disk-0  1.03T  14.1G      749M   13.3G             0B         0B      32G  default       285  -      -
volume      rpool/vmdata/vm-102-disk-0  1.03T  7.11G        0B   7.11G             0B         0B      16G  default      1422  -      -
volume      rpool/vmdata/vm-103-disk-1  1.03T   364G        0B    364G             0B         0B     750G  default       398  -      -
volume      rpool/vmdata/vm-103-disk-3  1.03T   277K        0B    277K             0B         0B       1M  default       310  -      -
volume      rpool/vmdata/vm-103-disk-4  1.03T  72.0K        0B   72.0K             0B         0B       4M  default      1309  -      -
volume      rpool/vmdata/vm-106-disk-0  1.03T  5.98G     10.7K   5.98G             0B         0B      32G  default      2241  -      -
volume      rpool/vmdata/vm-107-disk-0  1.03T  74.6K        0B   74.6K             0B         0B      32G  default      1880  -      -
volume      rpool/zva                   1.15T   406G        0B    279G           127G         0B     400G  default       435  -      -
filesystem  slowpool                    3.02T   501G        0B     96K             0B       501G        -  default        54  sa     /slowpool
volume      slowpool/vmbackup           3.51T   501G        0B     56K           501G         0B     500G  default        68  -      -
 



NAME                        COMPRESS        RATIO  DEDUP          RECSIZE  VOLBLOCK  PREFETCH  PRIMARYCACHE  SECONDARYCACHE  REDUND_MD
rpool                       zstd            1.08x  on                128K         -  all       all           all             all
rpool/ROOT                  zstd            1.00x  on                128K         -  all       all           all             all
rpool/ROOT/pve-1            zstd            1.00x  on                128K         -  all       all           all             all
rpool/backup_zfs            zstd-15         1.00x  on                128K         -  all       all           all             all
rpool/data                  zstd            1.00x  on                128K         -  all       all           all             all
rpool/data/vm-104-disk-0    zstd            1.00x  on                   -       16K  all       all           all             all
rpool/var-lib-vz            zstd            1.00x  on                128K         -  all       all           all             all
rpool/vmdata                zstd            1.09x  on                128K         -  all       all           all             all
rpool/vmdata/vm-100-disk-0  zstd            1.32x  on                   -       16K  all       all           all             all
rpool/vmdata/vm-101-disk-0  zstd            1.40x  on                   -       16K  all       all           all             all
rpool/vmdata/vm-102-disk-0  zstd            1.54x  on                   -       16K  all       all           all             all
rpool/vmdata/vm-103-disk-1  zstd            1.06x  on                   -       16K  all       all           all             all
rpool/vmdata/vm-103-disk-3  zstd            3.18x  on                   -       16K  all       all           all             all
rpool/vmdata/vm-103-disk-4  zstd            1.50x  on                   -       16K  all       all           all             all
rpool/vmdata/vm-106-disk-0  zstd            1.48x  on                   -       16K  all       all           all             all
rpool/vmdata/vm-107-disk-0  zstd            1.00x  on                   -       16K  all       all           all             all
rpool/zva                   zstd            1.08x  sha512               -       16K  all       all           all             all
slowpool                    on              1.00x  off               128K         -  all       all           all             all
slowpool/vmbackup           zstd-19         1.00x  sha512               -      128K  all       all           all             all

Any suggestion on where I should look would be gratefully received (ps I am new to linux & proxmox so please bear with me if I have to ask some obvious questions)
 
What does cat /etc/pve/storage.cfg show for the blocksize of the rpool/vmdata storage? Proxmox will use that value when creating a new virtual disk.

EDIT: You can also check and edit this value using the Proxmox web GUI of course.
 
Last edited:
What does cat /etc/pve/storage.cfg show for the blocksize of the rpool/vmdata storage? Proxmox will use that value when creating a new virtual disk.

EDIT: You can also check and edit this value using the Proxmox web GUI of course.
Jeezus I am a moron. Thank you

Missing the k ...

Because I had created a new dir and then copied everything in it didn't throw any issues, and I had forgotten it'd even done it until I was trying to work out how the hell I had managed that just now.
 
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