Storing VM's on networked drive .. ever any issues?

[cyr0n_k0r]

We want to move our VM's from being stored on the local servers drives to our SAN. Our reasoning behind this is if the server has a hardware failure and goes down, we can just import the VM from vmwares console on another server and simply start the VM again.

If this correct? Does anyone run their VM's this way? Do you see any performance issues with it being on a SAN (enterprise level, no soho) vs. the locally attached drive?

Also, I know when the VM's are running they "lock" the files, but if the VM goes down by means of a hardware failure, and I try and import the VM files into another server will I have any problems with corruption of the files or issues with them being locked?

I just dont want to try the import only to be told something stupid like "Your VM is in use on another machine" because the previous machine didn't fully release the files before it crashed.

 

[scoob8000]

I wouldn't see why it would cause a problem. Possibly performance wise depending on your SAN setup.

Why not try a real world test, setup a VM and manually crash the connection and see what happens.

 

[cyr0n_k0r]

I don't have any extra hardware right now that I can intentionally take down

 

[JTY]

I haven't had any trouble with running Xen VMs on an iSCSI SAN.

 

[FibreChanMan]

Lots of folks run their VMs in that config. They use VMotion for redundancy. So, if one host fails, the VMs would be ran on another availavble host in the VMotion cluster. With VMotion, VMs can also be moved between servers as needed to balance load on servers. So, if one server is overloaded, the VMs can be moved to a different server or two. As for performance. Most Enterprise SAN systems will have write cache, so they are usually pretty fast in reads/writes. One recommendation I can give, is if you go the VMotion Cluster route, when adding hosts to the cluster and making the hosts see the storage, don't use the add new storage feature, as it runs the risk of rewriting disk signatures when it scans for new storage. All you need to do is refresh the information in the storage window of the configuration portion of that host.

 

[ND40oz]

We run our ESX servers off of NAS appliances. No problems, just make sure you have gig connections to everything if you want to use vmotion. 4 ESX servers and two NAS applicances.