Adding RDM device to VM

[Niram]

Hi all,

I'm working on a very intensive QA testing environment which will include 1000 VMs and 1000 RDM devices exposed to each one of the VMs.

I'm looking for a way to expose RDM devices to VMs according to their LUNID and not according to their LUN names (/volumes/.../naa...).

Is there any easy way to do it?

Thanks for the help,

Nir

[LucD]

How will you map the LUNIDs to specific VMs ?

Is there a rule ? Or do you use an external file (.CSV) ?

[Niram]

Both options are actually exceptable.

1. All VMs are named according to convention VM1,VM2... so if I could map the 2 lowest LUNIDs to the first VM and the 2 after to second etc. it could do.

2. A CSV is also a good option.

I tried looking for both solutions but couldn't find anything.

Thanks,

Nir

[RvdNieuwendijk]

If you create a .csv file VmLuns.csv with the content something like:

VM,Lun

VM1,12

VM1,13

VM2,14

VM2,15

You can use the next script to add the RDM's to the virtual machines:

Import-Csv -Path VMLuns.csv | ForEach-Object {
  $vm = Get-VM $_.VM
  $Lun = $_.Lun
  $deviceName = ($vm | Get-VMHost | `
    Get-ScsiLun | `
    Where-Object {$_.RunTimeName.Split(":")[3].TrimStart("L") -eq $Lun}).ConsoleDeviceName
  New-HardDisk -VM $vm -DiskType RawPhysical -DeviceName $deviceName
}

Regards, Robert

[LucD]

I'm afraid there are a few flaws in this.

-) The LUNID alone is not enough to distinguish a LUN, you will also need the HBA, the controller, the target and the LunID

-) The Get-ScsiLun cmdlet returns all LUNs, also the ones that are already used by other RDMs or datastores. You will need to check if the LUN is already in use.

[Niram]

LucD,

-) Why would I need the HBA if I sepcify the ESX host?

-) As long as I know which LUNs should go to which VM I should be ok, right?

Thanks,

Nir

[LucD]

If you only have 1 HBA per ESX host, then indeed you do not need to specify the HBA.

LUNs can have the same LUNid but use different targets. For example

     vmhba1:C0:T0:L0

     vmhba1:C0:T4:L0

Which one do you mean with LUNid = 0 ?

Again, if your SAN infra is only using one target, you won't see this case.

[RvdNieuwendijk]

Hi Luc,

your points make sense. Changing the first point is not difficult. But I can't find a way to check if the LUN is already in use. Do you know how to do that?

Regards, Robert

[Niram]

Hi Luc,

By target you mean storage path right?

by the way, the script does not work for LUNID 0...

Thanks,

Nir

[LucD]

Let me explain that addressing scheme, it has to be interpreted as follows.

hbaname: the name of the adapter

Channel: a specific port on the HBA

Target ID: a storage controller

Lun: a single disk in the given target

Under a specific Target, the LunIds are unique, but not accross multiple targets and channels.

So you see a specific LunId multiple times on a HBA