Ed,
        Yes, to me anyway, 15 to 30 seems a fairly large number. Sounds
like you need something like backup to disk then clone/stage to tape. 
        Some of the advantages would be
Fast access (well certainly no slower than tape even the latest ones)
Immediate cloning (as soon as savesets finish instead of having to wait
until group finishes)
Multiple reads from the same volume will eliminate the contention you
mention
If you can keep the backups on disk for a time then you'll enjoy
extremely fast restores during that time (we aim for a week)
There are probably many more too....


But enough of the sales patter (but you might want to be thinking about
doing something like that in future). Have you though about scripting
the clones? You could have a set of scripts to do cloning at various
times during the day/night whichever suits you. You can sort the SSIDs
into order to optimise tape usage. You could even add some logic to
clone savesets that finished, say, an hour earlier (adjust this time to
reduce the risk of the saveset being on a taped currently being
written), that sort of thing

Regards
Bob

-----Original Message-----
From: Legato NetWorker discussion [mailto:NETWORKER AT LISTMAIL.TEMPLE DOT EDU]
On Behalf Of Ed Guenther
Sent: 08 March 2004 19:35
To: NETWORKER AT LISTMAIL.TEMPLE DOT EDU
Subject: [Networker] cloning


Brian,

re: no activity whatsoever.... how can I make sure that my clones
continue to run as scheduled?

We had crazy problems with cloning.  Since we have such a large
environment we have 15 to 30 target sessions going to each tape.  These
target sessions get intermingled with each other so that the tape drive
speed is kept high. We found that if we lower the target session value
the drive throughput isn't maxed out and our backup period overextends
itself.

But because of the high target session number (and other people, please
feel free to give your opinions on whether this is a high number
relative to your experience) the cloning takes forever.  For example if
we want to clone data from one system/server, its data is multiplexed
together with all the other data from other servers.  Furthermore if the
data we want to clone is on multiple tapes, we have to wait for the
other tape to become available--it MIGHT still be being used for
WRITING!  Lastly we have lots of tape drives but apparently not enough.
It would be a good idea to have dedicated drives used only for cloning.
This would keep them free and "ready" for cloning use.

Hope this make sense,

-Ed.

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