Some comments on this thread below...
>voila. when one of your DLT's needs cleaning, a TapeAlert signal will get
>sent, NetBackup will clean the drive, and after this happens frequently
>enough, your cron job will email you that your cleaning tape needs to be
>replaced. (note that this implies that you're running NBU 3.2 - I'm not

Only a few drive types support TapeAlert (most notably DLT7000 and STK9840).
I understood this was a new feature to 3.2. Earlier versions do not support
TapeAlert. 

Could some-one from Veritas explain what TapeAlert looks for as a signal to
initiate a clean? As Curtis says the drive privately informs the robot of it's
need to clean so how have Veritas hooked into this - or are we simply looking
for an 0x80 0x01 cleaning message in /var/adm/messages?

>The cleaning tape is abrasive and as such it will contribute to the
>wearing out of the expensive little heads of your expensive little
>DLT drives. :)

I'd just like to finally get to the bottom of this kind of statement. I believe 
it to be popular myth!
I too also believed that excessive cleaning of DLT drives would increase 
headwear however I've recently
been told categorically by an STK trainer that a DLT cleaning tape is simply a 
standard tape that has not
gone through the burnishing process. As such it's a standard tape (same 
thickness, same material)
as a data tape only not polished. Since it's movement over the heads is 
identical to a data tape it is
impossible to consider that it will increase headwear. I'm not saying this is 
the truth, but it's the
version of the truth which I currently believe :o)

Frankly the only thing overcleaning will hurt is your pocket - these tapes 
ain't cheap!

Does anyone have an evidence to contribute?

Alan