Is there a "fewest subfolders" allocation method?

[Raident]

For performance reasons, I would like to distribute my ESXi datastore VMs between as many different disks as possible, and each VM is 1 folder.

[jumperalex]

Are you talking about the vm.img or the data.img file?

 

I can't see having the vm.img being inside the array as being fast no matter how you allocate.  writes are just slow.  Reads at least won't run into concurrency issues but writes will because no matter what you have to deal with the single parity drive. Same would be said for the data.img but I can see the benefit might outway the speed hit.  Keep in mind, and you may not care, that depending on what you are doing with the VM it may keep your away spinning all the time.  If you concern is protecting those folders, you might be better off using a script to pause the VM, copy it to a backup folder on the array, and then unpausing.  So you get snapshot protection, but otherwise run at full non-array speeds.

 

That said, the simplest way I can think of to ensure each VM folder gets its own disk is to create a share for each VM and then specify which disc you want that share to use via the "include" field.  I say simple only because it is the easiest to understand.  The other way ...

 

Is to use Split Level 0.  You create your "VM" share with split level 0 and then you manually create the per disc folders and put the VM folders inside there.  Split Level 0 is "special" ... see here http://lime-technology.com/wiki/index.php?title=Un-Official_UnRAID_Manual#Split_Level_0