This article describes how to configure Thin Provisioning on storage repositories on NetApp Filers.
In previous versions of XenServer Thin Provisioning was only set on the LUN and not on the FlexVol. This document will help you to verify the status of Thin Provisioning on Storage Repositories created on NetApp filers.
When a new storage repository is created on a NetApp filer, you can select Thin Provisioning as an option at the time of creation. This means you can ot change the configuration on the fly. For XenServer 5.6 and earlier, Thin Provisioning was only set on the LUN as an option to the PBD (Physical Block Device) and so was not set on the volume itself.
With XenServer 5.6 Feature Pack 1, this changed so now new storage repositories created with the current version have Thin Provisioning enabled on both the LUN and the FlexVol on the NetApp. This can be verified with the following commands.
For the LUN:
lun show –v <lun path>
Just look for the Space Reservation field. This should be set to Enabled.
On the FlexVol side, run:
vol status –v <volume name>
This generates a large output but all you need to look for is the option “guarantee=none”. If that option is set, then Thin Provisioning is enabled on the FlexVol correctly.
To find out which options are set on an storage repository on the NetApp, the volume name as generated on the NetApp has the following format, with all spaces in the SR name replaced by underscores:
<SR name>__<first section of SR UUID>
For example, a storage repository with the name “Lab Storage SR” and a UUID of 5e5c55f4-e08c-21b1-37b6-300f6099b1e9 would have a volume name of “Lab_Storage_SR__5e5c55f4”.
The guarantee=none option can be changed on the fly on the NetApp, but this has no effect on the virtual disks created with XenServer. You must create the storage repository from scratch with XenServer 5.6 Feature Pack 1 to be able to use Thin Provisioning on the FlexVol as well as the LUN.