As most of you already know VMware Storage VMotion is the ability to live migrate a virtual machine from one storage to another without any downtime. The usage most IT Professional relate to VMware Storage VMotion is the following:
The ability to move your virtual machines from a storage or datastore to another for maintenance reason or storage replacement without downtime. Though I had just came to discover another reason where it became vital. Thanks to Vladan as he brought it to my attention when he commented on my previous post: VMware ESX 4 Reclaiming Thin Provisioned disk Unused Space
Yes, you will require storage VMotion in VMware ESX 4 to be able to reclaim Thin Provisioned disk unused space without downtime. As this is not a documented use of VMware Storage VMotion any where in the VMware Documentation I thought I will share it with all of you. If you had seen my earlier post VMware ESX 4 Reclaiming Thin Provisioned disk Unused Space, you will find out that you need to use Storage VMotion to reclaim thin provisioned unused disk space. Ok, there is other ways to reclaim Thin Provisioned disk unused space, but these require downtime. Below are one alternatives to VMware Storage VMotion to reclaim Thin Provisioned disk unused space, but remember it will require a downtime.
Follow up the same steps documented in my post VMware ESX 4 Reclaiming Thin Provisioned disk Unused Space, till you reach the Storage VMotion step then follow the below procedure:
1- Shutdown the Virtual Machine after you had run the sdelete on it.
2- Migrate the Virtual Machine to another VMFS datastore.
3- Power on the Virtual Machine.
Guess what being able to reclaim Thin Provisioned disks in some firms can save much more money on the disk cost to that would be spent on upgrading the VMware vSphere to a version where VMware Storage vMotion is included. I hope this help some one, & please leave a comment if you have any other way which does not require downtime nor storage VMotion as I could not find one yet.