Migrating from ESXi RDM to ESXi PCI HBA Passthrough

[BlueBull]

Hello everyone

I have quite a simple question, at least I think it's simple but I might be mistaken. I am planning on virtualizing unRAID using ESXi. Now, I have already spent waaaaaaay too much money this month on a new server, storage, parts,... because of course I did 😂 I don't yet have an LSI HBA to do PCI passthrough with and it's not in the budget anymore this month. I am however very eager to get started, so my question is: if I set up unRAID on ESXi using RDM disks, so passing through my disks connected to the onboard motherboard SATA connecters to the VM, can I then later when I have bought an LSI HBA, migrate my disks to PCI HBA passthrough without having to wipe my data? In other words, can unRAID volumes be migrated transparently from one passthrough method to another? I suspect this will not be possible because the UUID of the drives will change but I am looking for  confirmation

Thanks in advance!

Cheers

 

[doron]

@BlueBull,

 

The short answer is - yes, it can be done(*) (so, essentially, no - I'm not confirming your suspicion 🙂 ). Quite simply in fact.

 

As long as you are passing the drives through (i.e. RDM and not, say, whole-disk virtual drive), the transition to a passed-through HBA is possible, preserving your data. You will need to be careful with the procedure of making the change - let me know if you need guidance, I think there's some past stuff in this subforum - but assuming you do the right thing, you will not need to start fresh. (no issue with UUIDs). 

 

(*) Can be done - and I've done exactly that in the past.

 

[BlueBull]

3 hours ago, doron said:

@BlueBull,

 

The short answer is - yes, it can be done(*) (so, essentially, no - I'm not confirming your suspicion 🙂 ). Quite simply in fact.

 

As long as you are passing the drives through (i.e. RDM and not, say, whole-disk virtual drive), the transition to a passed-through HBA is possible, preserving your data. You will need to be careful with the procedure of making the change - let me know if you need guidance, I think there's some past stuff in this subforum - but assuming you do the right thing, you will not need to start fresh. (no issue with UUIDs). 

 

(*) Can be done - and I've done exactly that in the past.

 

That's awesome, that means I can already get started, sweet. Also very good to know that you have actually done this in the past, that is a much better answer than "it's theoretically possible".
This is great. I had indeed not expected this to be possible. It's quite impressive that it actually is, as most (enterprise) storage solutions are very finicky about things like UUIDs and migrations to dissimilar environments, protocols or hardware

Thank you very much for confirming this and for the offer of guidance. If I have any doubts at all during the migration procedure I will reach out for sure, better safe than sorry (though I do have off-site backups, of course)
I'll also go through the forum to see if I can find any information on this. I've already tried searching briefly but I have to admit that I only did a very quick sweep before posting here, it's very likely that I missed whatever information is out there

Cheers and thanks again!

Edited December 11, 2022 by BlueBull

[doron]

3 hours ago, BlueBull said:

It's quite impressive that it actually is, as most (enterprise) storage solutions are very finicky about things like UUIDs and migrations to dissimilar environments, protocols or hardware

Indeed they are, and impressive it is 🙂 

Unraid is quite straightforward in what it does with HDDs and, subsequently, what it needs from them. This is, IMHO, one of its strengths (it does come at a price tho). It builds an independent filesystem on each data drive, and maintains parity data so as to reconstruct them in case of failure.

Therefore, as long as there's a valid filesystem on the drive served to it, it will eventually work with that fs and be merry.