iSCSI/LVM confusion with enabled storage options

[tomrwaller]

Hi all.

Hoping for some advice and guidance for a new Proxmox user.

I'm in the process of standing up a cluster of 3 identical nodes backed by iSCSI storage for VM workloads.

I have created a bond of 3 NICS and defined the relevant networks for storage and enabled multipathing following the docs. Once multipathing was in, I created an LVM on top of that using the shell commands I found in this forum. All works so far.

The question I have is do I still need the iSCSI storage defined in the Datacenter - Storage options? If I remove it, all seems to function, until I reboot a host. When the host comes back up it loses comms to the LVM. I've also tried marking the storage as not active, but this results in the same. Seems odd to have the iSCSI in the list of the available storage options when instead I want to drive users to use the multipathed LVM.

I guess this presents another question, am I doing this correctly? I had assumed I could use just iSCSI without LVM but for some reason when creating a VM and selecting the storage whenever I selected the iSCSI storage it would never show the LUNs I've defined so I ended up mapping the LUNs and that seemed to work.

 

[wolfgang]

Hi,

and welcome here.

I try to understand your setup.
bond and multipath do nearly the same only on different layers. And the application layer is in most cases the better one. So if you use three NICs in a bond how have they connected to you SAN?

Normally if multipath is configured there is no need to keep the iSCSI entry in the storage configuration.
the config of the multipath dev are saved at /etc/multipath, but this can fail if the network is not ready.

You can use iSCSI direct without LVM but then you have to manage the LUN yourself and must create a LUN for every vdisk.