Re: [Networker] A few question on cloning

2010-10-22 12:08:35
Subject: Re: [Networker] A few question on cloning
From: George Sinclair <George.Sinclair AT NOAA DOT GOV>
Date: Fri, 22 Oct 2010 12:06:24 -0400
Skip Hanson wrote:
  Hello again. As you may know we added scheduled cloning to the 7.6.1
release. With your help we can continue to evolve this functionality.
Therefore, I have a few questions for you regarding how you script nsrclone.

  1. In what scenarios are you doing this?

We use cloning a lot. Certain special groups have automatic cloning enabled because they write their data to special tape pools (each of these groups uses a separate backup and clone pool). This is done on a daily basis, but having cloning done at the end of each group completion is not a major issue because there are never that many of these groups running in parallel so little to no drive contention.

However, most groups use the *same* backup tape pool, and cloning is not enabled and is manually done only once per month, following full backups. I have to run cloning manually for these because 1. there would be too much drive contention if cloning was enabled for those groups since there are many running in parallel, all using the same pool, and 2. it would force all backup levels to get cloned if I had it enabled; unless, of course, I set up different groups and schedules for the fulls versus the incrementals for each group - kinda of a pain. So I basically have to wait until all the fulls are done, and then I run the clones manually.

It would be nice if you could specify that cloning be carried out automatically, following a backup for the group, BUT only if it's a certain backup level, without having to create a separate group/schedule for each possibility. But that would only help for point 2. above, but not point 1.

  2. Do you make use of the -J option?

No. we're only using one storage node now.

  3. Do you make use of the -d option?

What does that option do? I don't see if for our release (7.5.1)?

  4. How do you schedule the clone operations?

As noted above, for the fulls, it's manual. For the special groups, cloning is enabled for the groups. We do also have two Oracle servers, and the Oracle backups for these (RMAN with NMO) are broken down into multiple groups, each group having cloning enabled. HOWEVER, it's very important for us that the groups be run in a special order. There is no reliable way to do this in the GUI, so the groups are disabled, and we run the backups from a script, using the 'savegrp' command for each group. This way we can force the order, with cloning automatically occurring after each group finishes but before the next one starts. That way, not only do they run in the right order, but there's no contention. Each of the Oracle servers runs its backups at different times. There's little overlap, but never a guarantee that there won't be some overlap. Regardless, both servers use separate backup and clone pools. Also, the server writes its index and bootstrap to a file type device, and cloning is auto-enabled for the group, with the clones going to tape, We also use staging to move the data on the file type device to a tape pool.

  5. Would the ability to chain save groups or clone operations be useful
(having a group or clone operation's execution tied to the ending of a
previous operation)?

YES!!!!!!!!!! This is something I've wanted for a long, long time. As I mentioned above, we have to do this manually now from scripts. Of course, you could guess what a reasonable time window would be for job completion and just have the groups start far enough apart to allow for that time, but it's a guessing game at best and would be inefficient best case. Having group C start only after group B and group B only after group A would be nice.

  6. Would the ability to have groups or clone operations just run once be

Not sure I understand what you mean here?

  Feel free to respond back to the list or to our usability alias at
networker_usability AT emc DOT com. Thank you again for all the help and 

On a somewhat related note, I notice that the group backup schedules allow only by week or month. Suppose I want to have a full run on the last Saturday of every month? If I select week, it will be every Saturday. If I select month, it will be on that same date (e.g. 30th) of every month which will not always be a Saturday. Sure, I can override the backup schedule manually, but that requires having to go in every month and dork around with it or set it all up months in advance - a pain when you're dealing with a lot of schedules and groups. So I solve this by running the full backups from a script that determines when that day is and then runs the full backups. The script runs from cron every day, so if it's not yet the date, it does nothing.


Skip Hanson
NetWorker Usability

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George Sinclair
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