How to migrate VTL to another DD

Here are the steps that I used to migrate DD VTL from DD880 to DD9500

1) My VTL was setup ages ago and is a based "directory" based VTL, not an MTree.  So I am going to setup basic directory replication from DD880 to DD9500. Note that we are simply replicating the pool that contains virtual tapes, things like virtual tape library (robot, drives), initiators, access group ..etc will be created manually on DD9500.

CTX   Source                                                Destination                                             Connection Host and Port                Low-bw-optim   Encryption
---   ---------------------------------------------------   -----------------------------------------------------   -------------------------------------   ------------   ----------
1     dir://dd880.mycompany.local/backup/vtc/ndmp_vnx5700   dir://dd9500.mycompany.local/backup/vtc/ndmp_vnx5700   dd9500.mycompany.local   (default)     disabled       disabled  
---   ---------------------------------------------------   -----------------------------------------------------   -------------------------------------   ------------   --------

When there is no activity on VTL i go ahead and create directory replication and initialize it. Here is my replication configuration, my VTL pool name is ndmp_vnx5700.  Once you initialize replication you can look on dd9500 under pools and you will see the pool appear and it will also show you how many tapes have been replicated so far (rough estimate)

2) Once replication is synced, schedule time to cut-over to new DD. With no activity on source, i went ahead and broke directory replication. Next i went to my library on dd9500 and imported all tapes.

3) This step is necessary unless you would like to convert your directory based VTL to an MTree. I wanted to do that because i like some of the reporting functionality you can get using MTree. So the very last thing i did in dd9500 GUI was to convert pool  to Mtree. That process took a couple of minutes because it has to stop and start VTL services. Once it completes you will your VTL pool in "mtree list" output.  I was curious to see where the tapes were moved to, so this process of converting moved the tapes from /backup/vtc/ndmp_vnx5700 to /data/col1/rsph_vnx5700/.vtc.  Not that i matters but i wanted to know for some further VNX/NDMP troubleshooting.

4) Last step for me was to present drives to VNX Datamovers and rescan. Drives showed up with new addresses

[nasadmin@Cs1 ~]$ server_devconfig server_2 -list -scsi -nondisks
server_2 : 
               Scsi Device Table
name                addr         type  info
gk01                c0t0l0       disk  1 000000000000APM00000000123
gk161               c16t0l0      disk  1 000000000000APM00000000123
jbox1               c64t0l0      jbox  STK L180 0306
tape2               c64t0l1      tape  IBM ULTRIUM-TD3 8711
tape3               c64t0l2      tape  IBM ULTRIUM-TD3 8711
tape4               c64t0l3      tape  IBM ULTRIUM-TD3 8711
tape5               c64t0l4      tape  IBM ULTRIUM-TD3 8711

5) We use Netbackup so we had to delete robot and drives and re-discover them.  Simply changing the address did not work because Netbackup definition contains the serial number in addition to the physical address on datamover.

6) Finally delete old VTL/Pool on dd880 when you are confident everything works on dd9500.