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ESXi and RDM?

no_connection

Senior Member
Joined
Dec 15, 2013
Messages
424
So I can't justify running a DL360 G7 just for FreeNAS or SCALE I was playing around with so I exported my pool from SCALE.
Installed ESXi 6.0 U3 and after a bit of head scratching managed to RDM the three drives I had in the pool. And add them to FreeNAS 11.3 U5 VM.
It did however not find the pool. I just made a new one no big deal since it's just for test with no data on it but my question is if it's something with RDM that didn't "transfer" or if pool from SCALE was incompatible? (SCALE was made with nightly a while ago if it matters).
Question two would be if someone have any experience, anecdotes or advice with RDM to share.

And to add disclamer, don't do this at work. And maybe not at home ether :P

I trust the RDM drives as much as I trust the VMFS5 drive ESXi is installed to. So about 3 on a scale of 1-10.
 

joeschmuck

Old Man
Moderator
Joined
May 28, 2011
Messages
8,949
I've been using ESXi for a number of years now hosting FreeNAS. I have used direct pass-thru and RDM, both work fine. I started with ESXi 5.5 and stepped through all the versions and am currently on ESXi 7.0.

As for RDM, if you had a properly working FreeNAS system where the data drives were working normally, RDM should have passed them through properly, provided you did RDM correctly. Since you are working on a test system, (this is the troubleshooter in me) you might want to repeat the scenario, go back to your original configuration using FreeNAS (I can't speak for SCALE, I've not used it) and create new pools for it. Then migrate back to ESXi as RDM. See if the problem is repeatable.

While RDM has worked for me and many others, I still prefer controller pass-through. Not from a reliability point of view but more because configuration is just easier.

I would never use VMFS5 for a data drive (except for small VM tests), hopefully that is not what you ended up doing, if so then you did not do RDM correctly. But you seem to have a lot of experience so I wouldn't think you did this incorrectly which makes me wonder if there is something weird about the format of the SCALE drives. You should be able to take your current pool and reboot into FreeNAS (bare machine) and the pool should be there for use.
 

jgreco

Resident Grinch
Moderator
Joined
May 29, 2011
Messages
13,189
So I can't justify running a DL360 G7 just for FreeNAS or SCALE I was playing around with so I exported my pool from SCALE.
Installed ESXi 6.0 U3 and after a bit of head scratching managed to RDM the three drives I had in the pool. And add them to FreeNAS 11.3 U5 VM.
It did however not find the pool. I just made a new one no big deal since it's just for test with no data on it but my question is if it's something with RDM that didn't "transfer" or if pool from SCALE was incompatible? (SCALE was made with nightly a while ago if it matters).
Question two would be if someone have any experience, anecdotes or advice with RDM to share.

And to add disclamer, don't do this at work. And maybe not at home ether :P

I trust the RDM drives as much as I trust the VMFS5 drive ESXi is installed to. So about 3 on a scale of 1-10.
Back in the day, before passthru was fairly reliable, we saw a lot of instances of shattered pools with RDM where something had gone awry and the users could never identify what had happened. That's why the virtualization sticky warns against it. Don't do it. If you must do it, replicate your pool somewhere safe.
 

no_connection

Senior Member
Joined
Dec 15, 2013
Messages
424
I would never use VMFS5 for a data drive (except for small VM tests), hopefully that is not what you ended up doing
I had a drive going unreadable after a lightning strike, drive seems fine but with no tools to repair or work with VMFS5 I learned my lesson, and going with what others experience it's not very good file system when things don't go perfectly. I do however install ESXi to HDD and use it for ISO and some VMs that don't rely on data. Like routers and stuff that I can just load conf into.

I figure it *should* work to RDM and have it show up. Maybe Ill test and make two VMs and see if it's something with ZFS going wierd.
At this point I guess I blame some sort of incompatibility between SCALE (nightly since that is what was available when I installed it) and FN. Could very well have been a too new ZFS version to run but I already made a new pool with the drives so I can't check.


And yes any data is not critical which is why I mess around with it.

The problem I have with the G7 is not enough drive ports and controllers to pass through. Unless I iSCSI boot ESXi but that is another fun project for the future.

And another quick question, 6.0 U3 is the last version supported for G7. Is there any use trying to get 6.7 running at all? I can't rally figure out if there is anything better from the later versions. And if it will run at all that is. Mixed wording from ppl on that part.

Is it worth going 6.7 for G8?
 

joeschmuck

Old Man
Moderator
Joined
May 28, 2011
Messages
8,949
Is it worth going 6.7 for G8?
Sorry, I can't answer that. But 6.0 should be fine for what you are doing, it's just a basic ESXi setup, right? I too like testing new versions of software on a VM, it's the safer way to do some things.
Back in the day, before passthru was fairly reliable, we saw a lot of instances of shattered pools with RDM where something had gone awry and the users could never identify what had happened. That's why the virtualization sticky warns against it. Don't do it. If you must do it, replicate your pool somewhere safe.
I cannot disagree with what Joe says however I personally have not seen anyone use RDM with failure until now, not since I have got into ESXi about 4 years ago, but that doesn't make the warning false, it just means I have not experienced it here on the forums. It is a good note of caution.
 
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