ISCSI multipath

[holest]

Hello!

I would like to ask a question about ISCSI Multipath.
I used your ISCSI Multipath and Proxmox VE 2.0 Cluster guides to setup my nodes.
If i use LVM its works, but in LVM i dont have the option to make qcow2 hdds, so i cannot use the snapshot function "only" the backup, and cannot make openvz containers.
So i tried to attach my storage other way.
Steps unchanged until i added ISCSI-s for my nodes at Storage/Add/ISCSI. Now i made 2 directorys /mnt/prox1 /mnt/prox2.
And mounted the the storage to there "mount /dev/mapper/prox30000 /mnt/prox1 -t ext4 mount /dev/mapper/prox20000 /mnt/prox2 -t ext4"
After that "Storage/Add/Directory" write there "/mnt/prox1" and checked shared option.
Now for example if i create a VM on node1 i only see it on node1 mounted directory, i have the option to Migrate it to node2, on webui even its look like to be migrated, but if i watch it in the directory of the node2 its still not there, stayed on node1 (and its broken because of "migration").
I don’t really understand, if i make something in the shared mounted directory, shouldn’t, it be visible on all the nodes because its shared storage?
What am i making wrong? Or is this iscsi multipath + mounted directory sharing not available only iscsi + lvm?

Thanks:
Holest

 

[dietmar]

You cannot use ext4 on a shared device - that simply will not work!

 

[holest]

Hi!

And thanks for the help.

You cannot use ext4 on a shared device - that simply will not work!

ok i tried with ext3:

mkfs.ext3 /dev/mapper/prox20000
mkfs.ext3 /dev/mapper/prox30000
#fstab
/dev/mapper/prox20000 /mnt/prox1 ext3 defaults 0 0
/dev/mapper/prox30000 /mnt/prox2 ext3 defaults 0 0

and with ntfs

mkfs.ntfs /dev/mapper/prox20000
mkfs.ntfs /dev/mapper/prox30000
#fstab
/dev/mapper/prox20000 /mnt/prox1 ntfs defaults,_netdev 0 0
/dev/mapper/prox30000 /mnt/prox2 ntfs defaults,_netdev 0 0

If i go inside the directories /mnt/prox1 or /mnt/prox2 i see the size of a storage 335.5 GB and 817.9 GB
but still not synchronized between nodes. I tried to put a 3 GB install disk inside one of them, i see it on that server and i see that there is a bit less hdd left, but on the other nodes it still show the full size of the disk and not the install disk.

We have a NAS too, i made an nfs share on it, i can attach it for all the servers, synchronized and perfect so i really don't understand it.

Holest

 

[dietmar]

We have a NAS too, i made an nfs share on it, i can attach it for all the servers, synchronized and perfect so i really don't understand it.

ext2,ext3,ext4,btrfs,ntfs, ... are local file system - you simply cannot mount them on several hosts at same time.

 

[holest]

Thanks for your answer.

Can i ask you, then what should i do?
We have an Fujitsu DX440 storage where we have two volumes prox1 and prox2, both enabled for our proxmox nodes IP through ISCSI.
How can we attach these volumes to our cluster as shared storage?
Sorry for my stupid questions without subscription, but my boss doesn't want to buy it until i make proxmox ha cluster that works with shared storage.
Or do i need an another server which can handle the sharing, like a dedicated nfs server? Or do i have to use LVM in this case?

Thanks:
Holest

 

[mir]

You have two "easy" choice right out of the box:
1) Apply lvm ontop of your luns
2) If your DX440 has a filer you can also distribute your storage through NFS

If you want to be able to make online snapshot go for 2) and use qcow2

PS. Above means HA for the VM. The storage never moves, what moves is the VM runtime from one node to the other.

 

[holest]

OK thanks
sadly dx440 doesn’t have this option, is there any way to install something like nfs server and client on all the nodes and use them at same time?
something like redundant nfs server from proxmox nodes to proxmox nodes vms?

 

[holest]

Is there any chance, to attach storage as lvm and share it as nfs from proxmox server.
i mean i install nfs server on all the proxmox nodes and use something like "Setting Up A Highly Available NFS Server" guide to make them communicate, and use the nfs share on vm-s?