Len,
On 09/09/2009, at 04:56 , Len Philpot wrote:
We've just implemented 7.5.1 in our first production environment,
which is
magnitudes larger than the test environment before it. We have 11
roughly
500 GB disk volumes we're backing up to, knowing that at some point we
will probably have to stage to tape (and the pools, tapes, policies,
etc.
are all in place for that). Right now, three of those volumes are
about
20-25% used and that's it.
However, the *default* Max Storage Period on our staging policy is 7
days,
which is waaaayyy too soon, causing our first test backups to already
stage to tape. I know what the values all mean, but I've not yet
spent a
lot of time in thought as to what the best combination of max storage
period, recover space interval and file system check interval is. But,
blindly staging after only 7 days is clearly much too soon. We'd
rather
have a reasonable high water mark trigger staging than time.
Question: Given that we currently have the adv_file space available
and
don't need yet to stage, are there any hidden gotchas we'll run into
if we
push the max storage period to, say, a month, and just keep an eye
on disk
volume usage?
Any change you make to the staging policy will come into effect
immediately, so if you want for the time being you can push your max
storage period out to a larger value, and then tweak it back down
later when you've worked out what your optimum options are.
As to tips/traps, the key thing of course is managing capacity of each
individual disk backup unit; NetWorker doesn't move backups from one
DBU to another if the first fills, so if that happens you'll have an
immediate staging requirement, which is where watermarks will come in
- indeed, watermarks should come in before that, but it doesn't quite
always happen depending on availability of tape, levels of activities
on the volumes and sizes of the largest savesets.
Best thing is if 7 day retention is too short, push it out, and
monitor how things go closely with a view to pulling it back down to a
"middle" point if a month turns out to be too long.
(As much as anything, determining optimum time on disk boils down to a
variety of factors including frequency of full backups, maximum size
of any individual saveset, number of tape drives available for cloning/
staging, whether you're cloning as well, etc.)
Cheers,
Preston.
--
Preston de Guise
"Enterprise Systems Backup and Recovery: A Corporate Insurance Policy":
http://www.amazon.com/Enterprise-Systems-Backup-Recovery-Corporate/dp/1420076396
http://www.enterprisesystemsbackup.com
NetWorker blog: http://nsrd.wordpress.com
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