This question comes up quite
a bit, and there is no really good answer. The manuals for many modern
drives (DLT, AIT, others) say to clean the drives only when they say they
need it (e.g. "when the light comes on"). The way this is done in
NetBackup is via the "TapeAlert" feature. You tell NetBackup that
the cleaning frequency is 0, and it will clean it only when the drive requests
to be cleaned. Unfortunately, there are many configurations under
which the TapeAlert feature does not work. As you can see in the
quote below, cleaning a drive too often can actually cause more harm than
good. You will need to find a frequency that works for you.
If TapeAlert doesn't work, I would start by talking to your tape drive
vendor. Ask them (a) why it doesn't work and what they're doing about
it, and (b) how often you should clean the drives in the meantime.
From: "Dave Pearson (EML)"
<Dave.Pearson@eml.ericsson.se>
We also have an L11000 and
haven't been able to get TapeAlert (cleaning when a drive requests it)
to work. Sun told us it is a known problem and they have reported it to
Veritas.
We used to clean our drives
every 20 hours until we started getting lots of media write errors. We
had all the drives replaced and the problems went away. The engineer said
the drives are basically self-cleaning and even if the light does come
on it usually goes out when the next tape is loaded. However, he suggested
120 hours as a reasonal interval for scheduled cleaning. So we set it to
that and, so far, no cleaning lights and no more errors.