3PAR VMware Thin Reclaim

[Nik]

Hi,

We have a vSphere 4.1 environment, with a T800 runing 2.3.1. All our VMware datastores are thin provisioned on the 3PAR. We are using the VAAI Plugin.

On the 3PAR Console, I can see the datastore Virtual Volumes and how much reserved user size has been used. If I use storage vMotion to migrate Virtual Machines off a Datastore, should I expect the reserved user size of the Virtual Volume to decrease (reclaim the space)?

[kn7671]

Nik - good question, I just looked at my environment and I do not see a one-to-one free space between what each VMware vSphere datastore summary and the 3PAR IMC VV reports, but on most of my VV's, I am seeing more free space available on the 3PAR VV's than I do in each VMware datastore.

For reference we are running a T400 on 3.1.1 (MU2) with mostly VMware 5.0.

[Richard Siemers]

There is a flag/policy to enable thin reclamation which defaults to off. I hear they will be changing it to default to on in a future release. In the mean time, you have to manually enable it either through command line, or in the gui with the "advanced options" check box enabled. If memory serves, its called zero_detect.

[ailean]

I thought the reclaim stuff was new in esx 5/3par 3.1.1... although my memory is fuzzy.
Seem to remember our esx peeps testing it after recent upgrades and it being a background process that they needed to nudge.

[Richard Siemers]

For vSphere 4.1 with a T800 runing 2.3.1, he's going to have to thin reclamation the old way, which was to enable the flag on the lun, then manually run a disk zeroing application on the host against the LUNs freespace.

Whats new in ESX 5 and Inserv 3.1.1 is the ability for ESX to tell the storage which blocks are now unused, and have the storage zero them out and reclaim them.