Nice quick and easy script with Powercli for identify the LUN names for each datastore.
This is useful for debugging the log files where only the LUN name is specified.

I am a big fan of Powergui where i run and create all my scripts in!
http://powergui.org/index.jspa
http://communities.vmware.com/community/vmtn/automationtools/powercli

Script:
(replace localhost with your own vcenter server)

Connect-VIServer localhost
Get-VMHost | Get-Datastore | where {$_.Type -eq “VMFS”} |
Select Name,@{N=”LUN”;E={(Get-ScsiLun -Datastore $_ | Select -First 1).CanonicalName}}

Disclaimer:
Please use this script at your own risk and test it out in your test lab first before using it in production.