Hi Perry,

Thanks for reply.

No, I do not want to convert to using mounted volumes (I am already) I want to shrink an existing LUN that holds tempdb and I want to do it on the fly, without taking the SQL failover instance down. If this is possible, I want to format the new unallocated space that will be at right position and create a new mounted volume with it.

Like I said, that volumen is running on a tier1 pool at SAN level. We do have the immediate request of moving a database to that tier1 space and this is the only available LUN at this moment.

For monitoring reasons, I want to divide that LUN and leave tempdb files on its own so my alert systems will be filtered correctly by mount point letter or volume. I understand the performance and I/O workload will be the same as it is actually the same pool or volume at SAN level.

Is that possible? Also, how critical this may be for tempdb on a Cluster that holds hundred of databases? On a live server the shrink process may take longer I guess or maybe crash the system?