Mixed Drives Same Media

Hi all,

We had 2 LTO5 drives using LTO4 media and everything was working great!. We recently added 2 LTO4 Drives (Still using the same media) and things are not so great :) Drives are marked as down and they get stuck in "mounting status".

Must I use different cartridge types when using mixed drives (same medai)? Do I have to setup 2 robots? All drives are part of the same library.

Also, Netbackup goes to mount a tape and the library gui shows that it's mounted, but, Netbackup is still stuck on "Mounting ...". Than, the drive goes down and it tries another drive.  Please help. Thanks!