VDI pools migration to new SAN + possible changes along the way

[zasran]

Hello dear community.

We are planning to migrate our 3 VDI pools to a new SAN.

Currently we use 2 datastores for all 3 pools on the old SAN and I will also create 2 new datastores on the new SAN.

We are using linked clones in all 3 pools, one pool uses persistent disks.

From what I have been reading I understand, that the migration can be done by adding new datastores to the pool and un-checking the old datastores.

That should then initiate a rebalance/recomposition of all the VDI machines - meaning that all the machines will be refreshed to the current snapshots of the golden images.

There is no easy way how to preserver the machine states in the process as far as I know.

In that process I also would like to upgrade the golden images to the current Windows 10 version 1909 and maybe do some small changes to them.

If the above statements are correct then this is my current approach:

(Per pool)

1. update the template VM and make changes, then create a new snapshot.

question - can I just make changes I need to the template VM? This should be fine since the composer should use the replicas to create new machines or refresh the existing ones

2. change the pool that is going to be migrated so that the composer uses the new snapshot

3. uncheck the old 2 datastores and check the new datastores in the Vcenter settings of the pool

4. initiate the rebalance of the pool - I think it's better to have all the machines rebalanced since I plan to do this during a weekend

Also I am not sure about the persistent disks. Will the persistent disks be migrated as well in the process and data on those disks will be preserved?

Is there a way how to convert a linked clone machine to a standard VM in case I need to preserve a specific VDI?

Please give me suggestions and answers to my questions if you already have experience with this.

Thanks in advance for your help.

Pavol.

[Shreyskar]

Hi zasran

Answering to your questions:

> Post rebalance task, linked-clone VMs are refreshed and OS disks are redistributed across available datastores. Only OS disks are reduced to their original size not the persistent disks.

> Rebalance does not affect View Composer persistent disks in any way. They are intact with user data and remains on same datastore as well regardless of the task you perform on desktop pool (recompose/refresh/rebalance)

> To migrate persistent disk to other datastore, there is a separate process. You can check Manage View Composer Persistent Disks

> You can convert a linked clone VM to a full clone standard VM. That will work however that standard VM should never be used as master/gold image in your horizon deployment. It is NOT officially supported (VMware Knowledge Base )

> Since user data resides on persistent disk, I am wondering why do you want to preserve VM state post rebalance as it defeats the purpose of having a persistent disk in place.

Mark the post as helpful/correct if it helps you.

[zasran]

Hello Shreyskar, thanks for the reply.

Actually we have 3 pools but only one has persistent disk.

We use to assign a specific VDI to a specific user in all 3 cases.

For those 2 pools with no persistent disks, I wanted to know, if preserving is possible.

But I see that it is not so I have my answer.

What do you think about my approach - is there something I am missing or doing wrong?

I will try to read a bit more about migrating the persistent disks in the meantime, if there is some easy way to also migrate the persistent disks to the new datastores.

[Shreyskar]

Hi zasran

For those 2 pools with no persistent disks, OS will be refreshed after rebalance task hence VM state and any local data can't be retained.

Other than that your steps looks fine but make sure you go through official documentation for migrating your Persistent disks Or open a support ticket for assistance in case of any doubt. Make sure you take backup of all persistent disks in vCenter prior to starting migration.