[Off Topic] Space reclamation on Compellent Storage Center

[m.novelli]

Hi guys, I'm installing a new storage Dell Compellent SCv2020 with vSphere 5.5 U3b for an existing customer

I have deep knowledge of Dell PowerVault storages but I'm new with Dell Compellent. I've read that making snapshots for backups or running Storage vMotion can affect free space on the storage due to native LUN thin provisioning: https://communities.vmware.com/thread/4 ... 0&tstart=0

The suggestion is to manually run or schedule the command "esxcli storage vmfs unmap -l MyDatastore"

I've tested a Storage vMotion and indeed the space on the source LUN remain allocated until manually "unmapped". I've not yet tested how Veeam Backup snapshots affect the free space on the storage because I've not yet migrated any VM on the new infrastructure.

Anyone here using Compellent Storage Center or similar storages with native LUN thin provisioning to share ideas and feedbackup? Many thanks guys

Marco

[Delo123]

Hi Marco,

as automatic UNMAP is currently disabled by Vmware you would in any case need to start a manual Unmap (can be scripted of course) as soon as you want to release some space previously allocated by which data however... Be aware unmap can put some serious load on your backend so don't schedule it under heavy production...

Ps. Don't unmap multiple luns at the same time (unless you have some superduper array like a pure storage which hardly blinks during unmap...)

[m.novelli]

Thanks for your feedback. Did you script the UNMAP tool or you run it manually? I've tested a couple of scripts in PowerCLI but they time-out after some minutes

Cheers

[Delo123]

Hi,

currently on holiday in Disneyland Paris, but I think you have to disable timeout with something like this
Set-PowerCLIConfiguration -ScopeSession -WebOperationTimeoutSeconds -1

There should be a good working script in the VMware communities (I believe the authors name was Matthew) which we slightly modified if I remember correctly.
Google should be able to find quite fast

Shouldn't you have found something I will send you our script when I get back!


Happy New Year!

[m.novelli]

Thanks, happy new year and enjoy Disneyland

[m.novelli]

Hi guys, I've found a super cool script to share with you: https://communities.vmware.com/message/2483410#2483410

The script is named vmware_unmap_datastore.ps1.zip - 3.1kbit

Be careful to run set-executionpolicy unrestricted before starting the script and also to create a C:\Temp folder.

I'm using the script in interactive mode, it is super fast due to advanced calculation of block size to use with UNMAP command. Default esxcli command on my 1 TB LUNs took about 4 - 5 minutes, with this script just a few seconds

Be careful to point the script to you vCenter server and to have at least vSphere 5.5. The script will automagically detect thin-provisioned LUN at storage level, so don't worry if you have a mix of thin and thick LUN on different storages. It will UNMAP only thin-provisioned LUNs

Marco

[timmi2704]

Hi Marco,
thanks for sharing your script.
Could you please check the provided link?

communities.vmware.com/.../2483410

[PMB_CTN]

timmi2704, see the URL below:
https://communities.vmware.com/message/2404689#2404689

[m.novelli]

Hi guys, the correct script is located on page 2 of the thread https://communities.vmware.com/message/2483410#2483410

It is called "vmware_unmap_datastore.ps1.zip" with a size of 3.1 Kbit

Marco