Cluster filesystem

[spearox]

Hello!

I'm new in clustering.
I want to set up my secound node and i have one iscsi storage.
I want to ask the community about possiblity.
I now use the iscsi as lvm and i formatted to ext4 because of thin provisioning.
Possible to use the same iscsi volume on two or more node with thin provisioning (qcow2)?

I yes wich file system i need to use?

Sorry i was realy new.

 

[LnxBil]

Hi spearox,

I suppose your storage is not on the two nodes, it that right? iSCSI can be shared, but you need a cluster file system for shared usage on both nodes. There is none officially supported by Proxmox on real shared storage, you can only use LVM and thick provisioning (Maybe also thin on LVM basis, but I do not know if thin provisioning works when clustered). A good starting point is the Storage Model article on the Wiki: https://pve.proxmox.com/wiki/Storage_Model

If you insist on using QCOW2, use NFS as your shared storage if the iSCSI lun can be converted to NFS on the storage side.

Best,
Andreas

 

[dietmar]

Maybe also thin on LVM basis, but I do not know if thin provisioning works when clustered.

No, thinLVM does not work - same problems as ext3/ext4 (not cluster aware).

 

[spearox]

Hi spearox,

I suppose your storage is not on the two nodes, it that right? iSCSI can be shared, but you need a cluster file system for shared usage on both nodes. There is none officially supported by Proxmox on real shared storage, you can only use LVM and thick provisioning (Maybe also thin on LVM basis, but I do not know if thin provisioning works when clustered). A good starting point is the Storage Model article on the Wiki: https://pve.proxmox.com/wiki/Storage_Model

If you insist on using QCOW2, use NFS as your shared storage if the iSCSI lun can be converted to NFS on the storage side.

Best,
Andreas

Yes you right.
So iSCSI only can be shared if I use LVM and thick prov.?
And if I want thin prov. in shared mode I need to use NFS share?
And in this case both node can write and read from same share at same time? So I can live migrate or create a HA?

 

[LnxBil]

So iSCSI only can be shared if I use LVM and thick prov.?

As Dietmar says, yes.

And if I want thin prov. in shared mode I need to use NFS share?

The only way possible, if you want to handle thinness on your client side. (iSCSI-over-ZFS as a NAS-Solution would also work, but you need to change your backend storage)

And in this case both node can write and read from same share at same time? So I can live migrate or create a HA?

Yes, NFS allows live migration.

 

[spearox]

OK. Thanks for replys and informations.

EDIT: Oh, one more. I can't use LXC Container over iSCSI and LVM? I now try it and i can't choose the LVM for the storage place.