jedijeff
2 Bronze

Reclaiming space not working for VMware

Hi. Has anyone successfully reclaim space? It seems for me sometimes it works and sometimes it doesnt.

We are on vSphere v6.5 and SCOS 7.3x.

I know the automatic UNMAP will not work because of the supported block size the auto unmap needs and Compellent doesnt use.

But the cli esxcli storage vmfs unmap should work right? 

So I had a 2TB volume which I emptied of a single VM awhile back. So VMware reported 2TB of 2TB free. 

Compellent shows 160GB that was sitting on Tier3.

We have 2 replay profiles on each datastore. 15min with 1hr expiration. And 24hr with 48hr expiration.

So earlier today I tried to reclaim it instantly, and this should work.

ran the unmap command from a hypervisor

Took a manual snapshot of the datastore

Then expired all other snapshots

At this point the space should have been reclaimed right?

 

0 Kudos
4 Replies
DELL-Bob Mi
3 Argentum

Re: Reclaiming space not working for VMware

You say you show space used in Tier 3. Is there any used space in Tier 1? If you only show 160 GB of used space in the Compellent this is most likely the configuration data which is stored on your disks. when the system is set up it puts configuration data on 5 disks as a back up. The size of the configuration files and metadata will depend upon the settings you use (Deduplication, Compression, single redundancy, dual redundancy, etc). But at this point all space besides the configuration should have been released.

If my answer was helpful, please click: Kudos
Forum Member since 2012
#iwork4Dell
0 Kudos
jedijeff
2 Bronze

Re: Reclaiming space not working for VMware

Unfortuneately I have also seen this with nearly 1TB of data that is in Tier3 and is not being used by VMware, ie the datastore is empty with no more VMs. 

I have taken manual snapshots after the reclaim and expiring them later to speed things up, or even waiting for our 2 day replay polices to expire.

I did turn the default auto relcaim off the datastore on VMware in case that was causing an issue.

But I think the issue is that VMFS6 has a maximum size of 1MB reclaim, and the SCOS default block is 2MB. Which we are.

So I am not sure how people are working, unless they modified their storage type datapage size to 512k?

For anyone who is working, I am curious what your datapage size is. 

 

 

0 Kudos
DELL-Bob Mi
3 Argentum

Re: Reclaiming space not working for VMware

VMWare forum post of same issue: https://communities.vmware.com/thread/586188

 

If my answer was helpful, please click: Kudos
Forum Member since 2012
#iwork4Dell
0 Kudos
jedijeff
2 Bronze

Re: Reclaiming space not working for VMware

Actually not mentioned in that thread, but looks like it was fixed in U2. We are still on U1 and some change. In VMFS-6 datastores, if you use the esxcli storage vmfs unmap command for manual reclamation of free space, it might only reclaim space from small file blocks and not process large file block resources. This issue is resolved in this release.
0 Kudos