Storage migration

[Spiros Pap]

Hi all,

I am running Proxmox 5.4-6 on a 3 node cluster.
I have a VM that consumes 15TB of storage, which is LVM based (it sits on FC storage). I would like to do a live migration of this disk, to a new storage (LVM storage, iscsi mounted on proxmox). Keep in mind that the VM is running and the disk is live, though the write load is not that much.

Is this possible? I don't care if it is going to take a week.. I only care about the data.
Does the live-storage migration guarantees that all the blocks, including the newly created ones (during the tranfer) will be migrated correctly?

I have done smaller (100G) disk migrations in the past with no problem. But that's another story, because now it is someone else's data...

Sp

 

[LnxBil]

Is this possible? I don't care if it is going to take a week.. I only care about the data.
Does the live-storage migration guarantees that all the blocks, including the newly created ones (during the tranfer) will be migrated correctly?

I have done smaller (100G) disk migrations in the past with no problem. But that's another story, because now it is someone else's data...

I don't see why it should not work as with other VMs. The data is migrated and the original version is untouched until the migration is finished and you checked the "delete source" box. If you do not want to delete the source, you will have the original version on FC, which is a good option if you're unsure if it works or not.

 

[Spiros Pap]

Hi again,

I would like to ask what is the technology behind storage migration.

Is the "source" disk snapshoted before migration (LVM based disk) and if it is, does that mean that the VG that the source LV (VM disk) resides on, needs to have extra room for the sectors written after the snapshot?

I am trying to understand the risks of the migration of a 15TB LUN.

Sp

 

[LnxBil]

Is the "source" disk snapshoted before migration (LVM based disk) and if it is, does that mean that the VG that the source LV (VM disk) resides on, needs to have extra room for the sectors written after the snapshot?

You cannot snapshot a shared/clustered LVM disk.

I would like to ask what is the technology behind storage migration.

It's QEMU/KVM internal, more information is here:
https://wiki.qemu.org/Features/LiveBlockMigration