Hi Paul,  Thanks for contacting EMC Community.  What you are seeing is  normal. When you delete the data from LUN, It will not zero out the deleted blocks on the array. With ZSR (Zero Space Reclamation) you cannot reclaim previously written but deleted tracks unless it is all zeros (which is rare to happen) or marked NWBH tracks, so the way we use to reclaim dirty tracks in windows OS is as follows:  If you are talking about w2k12,  it supports SCSI T10 TRIM, which is almost the same like UNMAP for ESX5.x so it will do the same behaviour. (It will set dirty tracks as NWBH and will be deallocated and returned to the pool)  For W2K8, There was an awesome tool called (Storreclaim.exe) however, it went EOSL in Q1 2013. This tool was using WRITE_SAME SCSI T10 so it will mark the previously written but deleted tracks as NWBH (fill them with zeros) and then you can run (start reclaim on tdev xxx) from SE host side. .  [NAME],Thin Reclamation Utility (TRU) is used for z/OS Mainframe not open systems  [URL]  [NAME], Yep, sDelete will do the same behaviour as with Storreclaim but you have to be careful when using it as you sDelete will fill up the whole free space on TDEV with zeros so you will see written and allocated tracks reaches 100% so no space for active applications using this tdev. (Personally, I won't recommend it, running unsupported storreclaim will be my first preference!)  Hope that helps Mohammed Salem
Hi folks,  I have a windows 2008 R2 host which is connected to VMAX. the lun size is 200GB. i have data of 180 GB in it.When i delete data from the LUN, for eg: 100GB in the host. however the space utilized in the backend thin device shows almost 90% used only.   Does the tracks in the backend will be 0'ed ??  If i use space reclamation the 0 tracks only freed up right?Why does the space is still showing as 90% used?  Cheers,Paul
When i delete the data from the host, in backend symmetrix vmax the volume 
doesnot reflect the space freed up