While there’s a TON of stuff going on (in the middle-to-final parts of EMC 2013 planning), I haven’t done a post in a while.
There’s plenty of great stuff, and I still haven’t been able to get everyone into the habit of always posting on the Everything VMware at EMC community.
So – without further ado, a couple useful vSpecialist threads that really should be on ECN… The first is from the always awesome Cody Hosterman (who writes the vSphere VMAX techbook), regarding the “state of the union” on Symmetrix and Space Reclaim. It’s notable that this is a space where things continue to change fast – so always check for the latest. Expect the behavior (disabled by default, manually triggered via vmkfstools) in vSphere 5.x to change in the future.
Couple of notes:
- Supported only on arrays running 5876.159 (5876 Q4 2012 SR a.k.a Marne)
- Vmkfstools may need to be run more than once to reclaim the desired amount of space. This is especially true when the input percentage is low (<50%). This is not a Symmetrix specific issue.
- UNMAP to a thin SRDF device is accepted and supported on the R1 and is propagated to its remote replicas (R21, R2) as long as the links are active and the remote boxes are also running 5876.159.
- Not supported on devices in use by Open Replicator for Symmetrix (ORS)
- Not supported with devices in use by RecoverPoint
- Not supported for encapsulated FTS devices
- Can be partially blocked by thin devices that have persistent allocations. The VMAX accepts the UNMAP command but respects persistent allocations. If the specified UNMAP range has persistent and non-persistent allocations, the VMAX will de-allocate the non-persistent allocations and leave the persistent allocations.
- Not supported with virtual devices (TimeFinder/Snap targets)
- Not supported with to devices involved in duplicate write sessions (temporary state; these sessions are used during meta reconfiguration and expansion)
- Not supported with TimeFinder/VP Snap targets
This and more is covered in a recent Whitepaper on VMAX, Virtual Provisioning and vSphere. As always – available for your reading pleasure! Click the link below…