[Veritas-bu] Separate Incremental and Full

2005-08-05 11:26:48
Subject: [Veritas-bu] Separate Incremental and Full
From: Mark.Donaldson AT cexp DOT com (Mark.Donaldson AT cexp DOT com)
Date: Fri, 5 Aug 2005 09:26:48 -0600
Nope incrementals only in a second policy won't work - the incremental is
scoped only within the same policy as its full.

You're going to have to make another policy with both a full and an

Set the full with a 52-week frequency and a wide window, probably over
several days.  Then do daily differential incrementals.  Each daily will be
changed files with respect to the 52-week full.  This backup set will have
to be kept for two years to guarentee a 1-year historical restorability. 

The reason for the two-year retention is because if you have to do a restore
from something archaic, you have to have something to base an old
incremental on.  You'll only run into trouble after the first year.  

The wrong way:

Week  Backup
----  ------
 1    Full 1 (1-year retention)
 2    Incr (with respect to Full 1)
 3    Incr (WRT Full 1)
51    Incr (WRT Full 1)
52    Full 2 (1-year year retention) 
53    Incr (WRT Full 2)  <<< Full 1 is now a year old and is expired
54    Incr (WRT Full 2)
Now, Joe Blow comes to you and says, "you keep a year's woth of files,
right?  Give me filesystem /blah/X from two months ago restored to
such-and-so location so I can mine data from it."

Now, you go to your old retention tapes and you'll need a bunch of
incrementals from weeks 1, 2, 40 & 42 and so forth but you'll first need to
restore the full backup they're based then apply the changes, right?  Well,
these incrementals are based on "Full 1" and "Full 1" is expired.  You've
got changes but no baseline.

You can keep the incremental for a year if they're cummulative incrementals
and not differental incrementals but  the baseline has to be kept for twice
your desired historical depth if you intend to have restorability.

Sorry - it's going to cost a little more tape than you anticipated.

You could dump your two week retention on of course, this method covers that
period.  If you need a daily full backup offsite, though, I think you're
running two policies.

HTH - Mark

-----Original Message-----
From: veritas-bu-admin AT mailman.eng.auburn DOT edu
[mailto:veritas-bu-admin AT mailman.eng.auburn DOT edu]On Behalf Of Ruben de
Sent: Friday, August 05, 2005 5:50 AM
To: Thomas Stewart
Cc: Veritas List
Subject: Re: [Veritas-bu] Separate Incremental and Full

You should put the incrementals in a different policy.

Thomas Stewart wrote:

> I have a policy with 6 schedules, one for each day of the week except 
> Sunday, each one does a full backup with a 2 week retention. The 
> purpose for these backups is disaster recovery.
> However if a user wants to restore a file that was deleted 3 months 
> ago, we are in trouble. For this reason I want to start some sort of 
> long term backup. As the data is quite static I decided long term 
> incremental backups would use the least amount of tapes. For instance, 
> a cumulative incremental each Sunday with a 12 month retention. 
> Initially I would need a full set of tapes, but for each subsequent 
> week I would only need 1 or maybe 2 tapes.
> I have tried this and it did not work as I expected:
> 01. Monday,     Full
> 02. Tuesday,    Full
> 03. Wednesday,  Full
> 04. Thursday,   Full
> 05. Friday,     Full
> 06. Saturday,   Full
> 07. Sunday,     Incremental
> 08. Monday,     Full
> 09. Tuesday,    Full
> 10. Wednesday,  Full
> 11. Thursday,   Full
> 12. Friday,     Full
> 13. Saturday,   Full
> 14. Sunday,     Incremental
> After some testing I realised that backup number 14 was doing a 
> cumulative incremental from the last full backup, which was backup 
> number 13. I wanted it to do a cumulative incremental against the last 
> cumulative incremental ie backup number 07. The problem with this is 
> that a file created and backed-up during the week on Thursday will 
> only be on tape with a 2 week retention, not the 12 month that I require.
> The main reason I want cumulative incremental is to save tape cost, 52 
> full sets of tapes will be megabucks. How do I go about solving this 
> problem?
> Regards
> -- 
> Tom
> _______________________________________________
> Veritas-bu maillist  -  Veritas-bu AT mailman.eng.auburn DOT edu

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