ADSM-L

Re: Recovery Log problems

1999-09-02 13:39:03
Subject: Re: Recovery Log problems
From: "Prather, Wanda" <PrathW1 AT CENTRAL.SSD.JHUAPL DOT EDU>
Date: Thu, 2 Sep 1999 13:39:03 -0400
I guess it depends.
I keep the recovery log in ROLLFORWARD mode and it works great.
I too use it largely because I can't afford the space to mirror the data
base right now.

The one time I did the ROLLFORWARD recovery, it worked beautifully.
It hasn't caused any problems once I got the log large enough - it does need
more space in ROLLFORWARD than in NORMAL mode, and if you don't have it
large enough for a day's processing it becomes a hassle.  My log is now 3
GB, compared to a 13 GB data base.  So mirroring the log and not mirroring
the DB saves me 7 GB.

I don't have any problems with the triggers because I force a DB backup
every day at the same time.  That clears the log, and so I don't have the
trigger

************************************************************************
Wanda Prather
The Johns Hopkins Applied Physics Lab
443-778-8769
wanda_prather AT jhuapl DOT edu

"Intelligence has much less practical application than you'd think" -
Scott Adams/Dilbert
************************************************************************


 firing DB backups at inopportune times.



> -----Original Message-----
> From: James SPORER [SMTP:james.sporer AT CCMAIL.ADP.WISC DOT EDU]
> Sent: Thursday, September 02, 1999 2:23 PM
> To:   ADSM-L AT VM.MARIST DOT EDU
> Subject:      Re: Recovery Log problems
>
>      I agree with Steve.  When the feature came out I thought about using
>      it instead of mirroring my database but I like to keep things simple.
>      I didn't want database backups occuring at odd times since I only
> have
>      two tape drives and I definitely didn't want to continuously mess
>      around with the recovery log.
>      Jim Sporer
>      University Of Wisconsin
>
>
>
>
> ______________________________ Reply Separator
> _________________________________
> Subject: Re: Recovery Log problems
> Author:  "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>  at IPNET
> Date:    9/2/99 10:13 AM
>
>
> > I also had to restore my DB twice.  Both times I was not able to roll
> > forward.
> > I am also wondering why I bother to set it since it has not helped me in
> > the past.
>
> I run in normal mode after trying rollforward for a while, and having it
> cause me more problems than it was worth.  I had a 5GB recovery log, and
> DBbackup's triggered in the middle of the night did not complete prior to
> the log filling, since client backups were running, and ADSM did not pay
> enough attention to the more critical DBbackup.  When it crashes, one must
> extend the log in standalone mode, and my server would then take over 4
> hours to come up.
>
> With mirrored logs, I dunno why one would bother with the problems
> associated with rollforward mode.  In the case were both logs go bad,
> rollforward recovery will not work anyway.
>
> We live with the fact that if we have to do a restoredb, we will have to
> re-backup all of the work since the last dbbackup.
>
> ...just my humble opinions...
>
> Steve (unVMix Systems Programmer/Dude) Roder
> (tkssteve AT ubvm.cc.buffalo DOT edu | tkssteve AT acsu.buffalo DOT edu | 
> (716)645-3564
> ,
>    | http://ubvm.cc.buffalo.edu/~tkssteve)
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