EMC VNX – LUN migration using VNX Snapshot

One of the VNX Snapshot use cases is to promote a snapshot to be a standard LUn. To do that, the snapshot must be attached, and then the SMP (Snapshot Mount Point) can be migrated to another LUN.  IF a migrating SMP has any snapshots associated with it (for example Cascading Snapshots), all of them will be destroyed.

mount SMP to another host

mount SMP to another host

Let’s discuss the case:

  • Host1 is a production server running an application with PrimaryLUN1 provisioned.
  • Host2 is a development server. This server must try a new version of the application on a copy of the production data
  • The Administrator performs the following actions
  1. Takes a snapshot ‘Snap2’ from the production PrimaryLUN1
  2. Creates SMP for a snapshot from PrimaryLUN1
  3. Provisiones SMP to Host2 (for example adds SMP to the storage group for Host2
  4. Attaches Snap2 snapshot to SMP
  5. Runs SCSI rescan on Host2
  6. Creates a local drive on Host2
  • At some point, SMP is snapped, and Snap2.1 is created

After some tiem of running development code on SMP, it is decided to promote it to an independent LUN. To do that, the Administrator performs the following actions:

  1. Create a new LUN, ‘LUN temp’ that is the same size as PrimaryLUN1. The new LUN does not have to be a pool LUN, or be in the same pool. It can be any LUN that is supported by the VNX array
  2. Starts a LUN migration session from ‘SMP Name’ to ‘LUN temp’
  3. When migration completed coupe of things occure:
    1. SMP Name Snapshot Mount Point is deleted
    2. LUN temp is renamed to SNP Name and retains all the SCSI attributes of the Mount Point, including WWN and even HLU ID within the storage group
    3. Snap2.1 is destroyed
LUN migration of SMP

LUN migration of SMP

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