On Fri, Oct 29, 2004 at 01:54:04PM -0400, George Sinclair wrote:
> How do folks determine this? How do you know how many tapes to add?
>
> Of course, I could just fill the whole library up and always keep it
> full, and then it's moot, but I'd like to avoid that. Up until now I've
> just been monitoring the tape usage by looking at the mount window (or
> nsrjb -C) from one week to the next to get an idea of how many tapes are
> appendable, and then I just kind of guess at how many tapes I think I
> might need to add, if any, based on the schedules that I know I'll be
> running. I've had no problems thus far because I have a pretty good
> understanding of the min. number required *BUT* I'll soon be leaving
> these decisions up to two trainee operators, and I'd prefer to have a
> script to help them with this until they become more familiar with the
> operations. Such a script would help me, too. I think I can write it,
> but I need help with items 1 and 2 above which seem necessary.

It's probably possible to script something with some savegroup probe
calls, and some mminfo calls to determine which media is
available/loaded in the library/how much space is left.  However, I'm
not sure if there's a good benefit from all of that work.

I have about 16 slots I use for Daily tapes.  Before I leave for the
day, I bring up the nwadmin GUI and look at the Volumes tab at the tapes
in the library.  I usually swap them out in banks of 8 ... if all of the
tapes in those 8 slots are full, I take them out and put the next
available 8 tapes in.  In my environment, that can buy me a couple of
days, or one day (depending on how often people like to rename their
large data sets...grrr)  If something did go wrong and I didn't get
enough tapes, Networker send an email that routes to my pager.

In other words, I try to keep the most recently Daily tapes online in
case someone needs a restore from last night's backup.  But, I don't
worry about loading too many usable tapes in the jukebox because I know
they're going to be used (and if they need a restore I can always put
them back.)  I'd recommend going with something similar for your junior
operators, and if that doesn't work in your environment, have them help
come up with solutions.  :)  That's what it comes down to, doesn't it --
if there aren't enough tapes in the jukebox, it's their job to put them
in -- if a tape out of the jukebox was needed for a restore, it's their
job too.

Dave

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