I using NBU 4.5 Data Center on Solaris with acsls library.  We are using
LTO Gen2 drives and I still do not see
any drives getting cleaned with over 400 hours of use on any particular
drive. Everyone is telling me they do not need to be cleaned. I'm not
buying it.  I think something is not configured right.  This is what I'm
looking at.

If I do a tpconfig -L , the cleaning frequency is not set.  I changed one
of the NBU options by the following:
tpconfig -update -drive 0 -cleanfreq 100.  This is suppose to set indexed
drive 0 to need to be cleaned
after 100 hours of usage.  When I looked at the drive status again with
tpclean -L, it now has a comment at
the end of the line that says NEED_CLEANING which it should.  The cleaning
frequency field still says 0 tho...
So when will it get cleaned again?  At next backup job execution?  Is this
the right way to have drive cleanings
done.  Some folks say let ACSLS do it.  I have it set there too, but as I
said it still has not cleaned a drive.