Multipath iSCSI problems with 8.1

[bbgeek17]

Yes, I know that iSCSI ist legacy tech, and I avoid it where I can, but still a lot of customers of me, especially those coming from VMWare often bring iSCSI Clusters.

Although NVMe/TCP is gaining steam, I wouldn't put iSCSI into the legacy column. With proper implementation, it can still provide a lot of oomph to the user. iSCSI is an industry-standard (there is a built-in initiator in every OS) way to access block storage.

@Lephisto , do you or the customers you are helping have appropriate PVE subscriptions? Have you raised a case through the support portal? Forum works great for many things, but if you have a critical issue, direct contact is always the best approach.

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

 

[Lephisto]

I have community subscriptions but this shouldn't make a difference. Changes in the last Proxmox releases have just broken Multipath support, I don't see why I should need a more expensive subscription.

Might be that iSCSI is still in use, but at least Proxmox is treating it legacy'ish? It's two perl modules that carry the problematic code, but so far no statement from Proxmox.

 

[bbgeek17]

Changes in the last Proxmox releases have just broken Multipath support, I don't see why I should need a more expensive subscription.

I sympathize with your plight. The breaking change should have been configurable IMHO.
However, Multipath continues to work just fine for our customers who use iSCSI.

On the other hand, the change exposed a flaw in badly designed storage systems. They should not be leaking internal IPs to clients. That is just bad architecture.

You have a few options: a) wait for PVE developers reply/decision b) roll-back the change (you can find pre-change versions in github, or older ISOs) c) implement filter yourself

I'd say your most immediate path to resolution is to rollback to pre-change versions.

Good luck

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

 

[Lephisto]

yeah, but proxmox is not exactly designed for rolling back things. I already thought about just replacing the perl modules manually, but still this is not exactly nice

 

[bbgeek17]

already thought about just replacing the perl modules manually, but still this is not exactly nice

That is exactly what I meant. Not the whole system.

Track down the change in the Dev mailing list or via RO github mirror and "un-patch" the relevant files. Obviously this would not be a supported/recommended path. Testing that it works and is not overwritten by next update will be completely on you.

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

 

[miguelhmv]

I am very disappointed with this issue.

Not all interfaces on my storage solution have IPs on routable networks for my PROXMOX server. Not a problem for Windows, Linux or even PROXMOX 7.x clients, but after upgrading to PROXMOX 8.x, all interfaces in my iSCSI storage solution are discovered and multipath is forced, retrying impossible connections over and over again, degrading disk access.

I propose a temporary workaround, not a solution, be careful in production environments!, but maybe it will help you.

1. Stop VMs that are using iSCSI drives.
2. Run iscsiadm -m node -o delete -T your_IQN --portal yourIP:yourPORT in order to delete autodetected portals -don't delete the portal you used to create te ISCSI destination!- (you can see iSCSI portals for your under /etc/iscsi/<your_IQN> folder)
3. Restart iscsi service: service iscsid restart
4. Start the VMs that use iSCSI drives

Performance graphics under Summary section and iSCSI access to the drives should work.

 

[Lephisto]

Yeah, i also work around with it through iscsiadm -m node -o delete [..] but it's really really annoying.

I know that it#s basically the iscsi vendors wrong implementation, but previously proxmox behaved in a way that it was easy to work around. It would really be good to get a feedback of a proxmox dev.