Mirrored VMFS volumes

[rimvydukas]

Basic question: Is there a way with ESX 4.x to "mirror" your VMFS volume?

In other words, for high-availability, I would like to have two

entirely separate storage arrays each have a 300GB LUN, and present it

to the ESX server, then put one 300GB VMFS volume mirrored

across the two 300GB LUNs. So that if either storage array (or path to

it, or whatever) goes down, the VMFS and virtual servers hosted on it

will keep humming along with no problems.

I know this can be done natively on Windows Hyper-V server, for example..

Just to be clear - I am not talking about MPIO, which I believe is just

about multiple-paths to the same LUN. I'm talking about two different

LUNs presented from two different arrays. I looked at the ESX VMFS

extent option, but that seems to be about extending a VMFS across

disks, not mirroring it.

I'm also aware I could do this with an external software or hardware-based storage virtualization platform, but then that

becomes a single-point-of-failure (or at the very least, ends up

costing me more money). I really want to do this host-based (ie on the

ESX server).

Thanks in advance.

[AndreTheGiant]

You can do a "mirror" at different level:

• storage base replication: you must have two compatible storage and a feature for keep the replica (for example for EMC is called MirrorView)

• datastore replication: VMware does not have nothing for it, but you can check for Double Take product (for example)

• file replication: you can create a rsync script that periodically make a snap, copy the file, and remove the snap

• VM replication: see for example Veeam Backup or Vizioncore vRanger

Andre

[rimvydukas]

Thanks for the answer but I do not want replication, I want mirror. We have two HP EVAs and we want to be able to run guests without any crashes when one array goes down.

As for now I do soft mirror at the guest os level but this option is only temporrary workaround as it has shortcommings.

Hardware mirroring at the storage level is not an option too at least for us:(

But thanks for the answer.

[AndreTheGiant]

we want to be able to run guests without any crashes when one array goes down.

I do not know if is possible directly with EVA.

Usually you have to put a virtual layer at the top of your storage.

For example with DataCore SANmelody product.

Andre

[whynotq]

ESX does not have a configurable volume manager so you can't create a mirror at the ESX level, as Andre points out, there are options such as Array based (Datacore) that can give you what you are looking for but at a price $$$. Then there are application availability tools (CA WanSync, EMC Replistore, MSCS). One other option that you may want to look at http://www.stormagic.com/products_SvSAN.php which is designed i know to work with local storage but my understanding is that at the heart of the appliance is the ability to mirror "non-shared" storage for presentation to ESX clustered hosts as shared storage via iSCSI, it may be of no use to you as you sound like you run SAN based shared storage but then again it may be an answer.