Tip of the Day: Unmap and iSCSI

Today’s Tip…

Occasionally, I see questions on discussion aliases and think to myself that they might make good tips.  This one pops up every now and then.

Q. Does Microsoft’s inbox iSCSI target support UNMAP?

A. The quick answer is no.  Windows Server 2012 and 2012 R2 support thin provisioning in that they attempt to communicate with the storage subsystem and tell it when sectors are no longer in use.  The storage device can then repurpose those sectors as it sees fit.  It does this by using SCSI UNMAP 0x42.  However, the storage subsystem must also support this for it to function.  And the inbox iSCSI target does not.

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