It will only reclaim completely-zeroed out blocks so if Windows allocated those blocks for whatever reason with non-zero data (at any point) Symmetrix zero-based reclaim will not be able de-allocate them. So i would say that the free space in your windows volume is non-zero (previously deleted data or paging files or temporary files etc...) So what I would recommend is running the sDelete program within your Windows VM (downloadable from Microsofts website) which will zero out all of your free space. Then re-run the zero reclamation process on that TDEV. I will suspect that you will see much closer to the 200GB of used space at that point.  Hope this helps  Cody
Hi,  I'm starting to test VP LUNs presented to ESX 3.5 .  Here is the scenario: - One VM(win 2003) of 265GB with 75GB of free space inside the VM. - One Thin pool with a thin device of 500GB.  We have storagevmotionned the VM to this new thin device. Usage in the pool was 270GB. I ran a space reclaimation and the usage went down to 250GB. I was expecting it to go down around 200GB.   From readings I've found that the zeroedthick format is the VP friendly one and I was expecting that since the blocks are not initialized my real usage in the thin pool would have been 200GB.  Do you gus know how it's supposed to behave ? Could it be related to the version of ESX ?  Thanks
Virtual provisioning behavior with VMWare