Networker

Re: [Networker] Advice needed on staging policy values

2009-09-08 17:23:31
Subject: Re: [Networker] Advice needed on staging policy values
From: Preston de Guise <enterprise.backup AT GMAIL DOT COM>
To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
Date: Wed, 9 Sep 2009 07:04:37 +1000
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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