Shared ISCSI Storage VG's?

[ajezierski]

I have a 4-host cluster (DEV-PVE) with an SAN providing shared storage via ISCSI. The SAN is presenting 2x storage targets w/ 3x LUNS. I have multipath configured and and the ISCSI targets added to the datacenter storage section. I'm at the point of adding in the LVMs but am stumped as to how may Volume Groups to create. Note, this setup is to migrate off of a VMware environment using vVOL's (easy storage management) to this PVE cluster (DEV-PVE) so that I can then re-configure the current prod VMware and SAN environment to a what will be the new PROD-PVE cluster (4-hosts).
Is it best to have 1 storage group with all the LUNs or 1x LUN per storage group?
LUN-1 = 10TB
LUN-2 = 10TB
LUN-3 = 15TB

Any advise would be much appreciated.

 

[bbgeek17]

Hi @ajezierski , welcome to the forum.

You need to create LVM using the Multipath DM device, not the underlying direct physical devices. So to answer your question - one VG per unique LUN.
In your case 3 Volume groups (or you can combine your LUNs into a single VG).

You may find this article helpful: https://kb.blockbridge.com/technote/proxmox-lvm-shared-storage/

Is it best to have 1 storage group with all the LUNs or 1x LUN per storage group?

This is really up to you. Why did you create 3 LUNs in the first place? Are they all part of the same RAID group? If they are, why not reconfigure as single LUN? Do you want a single storage pool to manage? If yes, combine them together. Do you want to have isolation across the VMs - keep them separate.

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Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox

 

[ajezierski]

Hi @bbgeek17, and thank you for responding.
Your comment on why I created multiple LUNs is a good question. They are all on the same SAN and RAID/hybrid storage (EMC Unity 300). When I had it configured for a VMware environment, I had a single/large vVOL presented to vCenter. For my environment, it worked great.
I was under the impression that in a PVE setup, using the same methodology wasn't recommended and that I should spread them out amongst multiple LUNs for overhead purposes...exp only a couple of VM's per LUN. But if it's suitable to create 1x large LUN for everything, I would prefer that instead.
Please advise...

 

[bbgeek17]

There may be a slight advantage of having multiple LUNs and Multiple Targets from a queue depth perspective. However, that generally applies to very high performance storage with fast clients.
Without knowing anything about your performance profile, and based solely on the fact that you have a mid-range hybrid array, I suspect you will be fine with single LUN. PVE does not prefer one way or the other.

Perhaps your storage vendor SE can advise for your particular SAN device.

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Blockbridge : Ultra low latency all-NVME shared storage for Proxmox - https://www.blockbridge.com/proxmox