Just for note a bug.

If you modify the iqn of the target iSCSI Celerra, if you don't let the default one.

The SRA is not able to find the good name of the target when it make the command to find the name.

The log :

2011-11-08 12:43:28,520 [com.emc.util.net.SSHConnection]: 172.18.12.119 Executing command:  /nas/bin/server_iscsi server_2 -snap -list -target  -lun 2 | grep -e 'ckpt[[:digit:]]\+ '
2011-11-08 12:43:28,583 [com.emc.util.net.SSHConnection]: 172.18.12.119 Command result: stdout: (), stderr(Error 2100: Usage:
server_iscsi { ALL | }
-snap
-list [ -target [ -lun ] ])

So if you got this error recreate your Celerra Target iSCSI and let the default iqn.