Navisphere Command Line Interface (CLI) Reference - VMware Communities

Reserved LUN Pool CommandsIntroduction to the reserved LUN poolThe global reserved LUN pool works with replication software, suchas SnapView, SAN Copy, and MirrorView/A to store data orinformation required to complete a replication task. The reservedLUN pool consists of one or more private LUNs. The LUN becomesprivate when you add it to the reserved LUN pool. Since the LUNs inthe reserved LUN pool are private LUNs, they cannot belong tostorage groups and a server cannot perform I/O to them.Before starting a replication task, the reserved LUN pool mustcontain at least one LUN for each source LUN that will participate inthe task. You can add any available LUNs to the reserved LUN pool.Each storage system manages its own LUN pool space and assigns aseparate reserved LUN (or multiple LUNs) to each source LUN.All replication software that use the reserved LUN pool shares theresources of the reserved LUN pool. For example, if you are runningan incremental SAN Copy session on a LUN and a SnapView sessionon another LUN, the reserved LUN pool must contain at least twoLUNs - one for each source LUN. If both sessions are running on thesame source LUN, the sessions will share a reserved LUN.Allocation of the reserved LUN poolThe software allocates reserved LUNs on a per source LUN basis.Each storage system manages its own reserved LUN pool space andallocates reserved LUNs on a per-source LUN basis, not a per-sessionbasis. For example, if two replication sessions are running on a sourceLUN, the storage system assigns reserved LUNs, as needed, to thesource LUN, and both sessions share these LUNs.The assignment of reserved LUNs is based upon the first availablefree LUN in the global reserved LUN pool. An adequate number ofreserved LUNs is essential because the software will terminatesessions if no free LUNs are available in the global reserved LUNpool. If you are running multiple sessions per source LUN and yourreserved LUN fills up (runs out of space) and no free LUNs areavailable in the global reserved LUN pool, the session that is trying toallocate a reserved LUN from this pool will terminate.354 EMC Navisphere Command Line Interface (CLI) Reference