We recently upgraded from 7.2.2 to 7.4.1 and then to 7.4.2. and I wish we did not have to do it.
The upgrade process from 7.2.x to 7.4.x is irreversible as the database structure is different in 7.4.x and the upgrade changes the structure. So in preparation for upgrading I would recommend making a copy of your indexes so you can quickly revert back if you have problem.
I would also recommend making sure you have your licensing in order as you need an upgrade license in order for it to function after the upgrade. If you have VTLs you may need to trade in a physical tape library license for there new VTL style license.
We we forced to upgrade for several reasons:
1) There was is a feature in 7.4.x that allows you to have a different retention policy on a clone from the original backup. We needed this as we did not have space on our VTL to keep retentions as long as we wanted on the physical tapes.
2) We had a problem that we were told was fixed in 7.4.1. It turned out to be something else.
3) 7.2.2 was soon to be EOL.
We have found 7.4.1 to be very buggy and were told the fixes to our problems were in 7.4.2. This was a minor upgrade, but still requires an uninstall and re-install of the Networker packages (our server is running Solaris). We have also found 7.4.2 to be buggy.
The major issues we have had in 7.4.x is with the job database which is new to 7.4.x (not sure if it was in 7.3.x as we never ran that version). There is a problem were occasionally it corrupts itself and EMC support can't tell us why this happens. In fact EMC support has kind of admitted that there is a huge problem with the job database and they don't seem to know how to fix the bug. In order to fix the corruption we have had to stop Networker and remove the database and restart.
The indexes also seem more prone to corruption if Networker is not shutdown cleanly than it was in 7.2.x
Other issues we have had is the removal of LUS driver support in Solaris 10. Networker now uses the Solaris sgen drivers and many of the old sj* commands no longer work. It took a lot of research to figure out how to discover jukeboxes and get get the correct tape drive order. EMC support was not much help, pushing the issue off to everyone else (OS vendor, HBA vendor, tape library vendors etc)
The new version also seems to be more tied to DNS and we had a lot of problems getting Networker to start up fully in our DR testing.
There is also a new web based GUI in 7.4.x (which I believe was introduced in 7.3.x) and they took away the old nwadmin X-based GUI. Although, we have hacked it so that we can still use nwadmin - we use it only for display purposes and do all the configuration in the new GUI. The new GUI has a lot more functionally, but takes some getting use to if you used nwamdin. The nwadmin GUI is better for seeing what activity is going on as the new one is more drill down to look at individual objects.
I would have to say that we found 7.2.x to be far more stable and robust than 7.4.x.
