[SOLVED] KVM on CephFS - Not possible?

[wahmed]

I am trying to install a VM on CephFS shared storage. No matter which format(qcow2,vmdk,raw) i try, i keep getting this error message when i try to power on:

  [COLOR=#000000][FONT=tahoma]kvm: -drive file=/mnt/pve/fs-ceph-01/symmcom/images/100/vm-100-disk-1.raw,if=none,id=drive-ide0,format=raw,aio=native,cache=none: could not open disk image /mnt/pve/fs-ceph-01/symmcom/images/100/vm-100-disk-1.raw: Invalid argument[/FONT][/COLOR]

CephFS is setup properly because i have installed Containers on the same storage and they are working fine. Its the KVM that cannot be started.
I knew CephFS is still not matured enough. Just wanted to see what performance i get with a VM on it.

 

[udo]

Re: KVM on CephFS - Not possible?

I am trying to install a VM on CephFS shared storage. No matter which format(qcow2,vmdk,raw) i try, i keep getting this error message when i try to power on:

  [COLOR=#000000][FONT=tahoma]kvm: -drive file=/mnt/pve/fs-ceph-01/symmcom/images/100/vm-100-disk-1.raw,if=none,id=drive-ide0,format=raw,aio=native,cache=none: could not open disk image /mnt/pve/fs-ceph-01/symmcom/images/100/vm-100-disk-1.raw: Invalid argument[/FONT][/COLOR]

CephFS is setup properly because i have installed Containers on the same storage and they are working fine. Its the KVM that cannot be started.
I knew CephFS is still not matured enough. Just wanted to see what performance i get with a VM on it.

Hi,
you can try cache=write through - perhaps this change anything?!

Udo

 

[wahmed]

Re: KVM on CephFS - Not possible?

Hi,
you can try cache=write through - perhaps this change anything?!

Udo

This actually worked!! Never thought cache settings would prevent a freshly created VM to start.
Thanks a million Udo!

 

[dietmar]

Re: KVM on CephFS - Not possible?

This actually worked!! Never thought cache settings would prevent a freshly created VM to start.

AFAIK cache=none tries to open with O_DIRECT, and that is not supported by ceph.

 

[wahmed]

Re: KVM on CephFS - Not possible?

AFAIK cache=none tries to open with O_DIRECT, and that is not supported by ceph.

I am assuming this only applies to CephFS and not the RBD? Because all virtual disks works fine on RBD Storage with or without cache.

 

[dietmar]

Re: KVM on CephFS - Not possible?

I am assuming this only applies to CephFS

yes