No, only the last full database backup could be used to do a restore using
the recovery log files. Remember after every full database backup the
recovery log files get reset (if your in rollforward mode which it sounds
like you are).
Mark
-----Original Message-----
From: Johnson, Milton [IT] [mailto:milton.johnson AT CITIGROUP DOT COM]
Sent: Tuesday, February 17, 2004 1:43 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: Question on Restoration from DBSNAPSHOT
Mark / Mike,
Nice to here from you Mark. I am aware that DBSNAPSHOT can only be used for
PIT restoration, at least after refreshing myself, and that only the BACKUP
DB FULL/INCR resets the recovery log. What I'm now asking is can I make two
DBB (full), one immediately after the other, and then use either one to do a
restore to the point of failure using the recovery log?
Thanks,
H. Milton Johnson
Voice: (210) 677-6728
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of
Mark D. Rodriguez
Sent: Tuesday, February 17, 2004 10:23 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: Question on Restoration from DBSNAPSHOT
Hi Milton,
It's been a long time since we talked. You know you could have just called
me and I would have helped you out. But anyway here is what I
recommend:
DBSNAPSHOT - should be used for your DR backups of the DB. They should be
to a tape and taken offsite with your DR tapes. DBSNAPSHOT is effectively a
full backup of the DB, but it does not involve the LOG in any way.
Therefore, it can only be used for a PIT (point in time) restore. Also,
please note that a DBSNAPSHOT does not reset the LOG like a DBB (full or
incremental) does if the LOG is set to ROLLFORWARD.
This makes it perfect for a DR type restore since in a disaster you would
expect that the LOG would be lost. Please note if you are using DRM then
you should update your scheduled Prepare command to include "Prepare
Source=DBSnapshot" so that it manages the correct tapes for you. I sure do
wish that the ITSM developers would make this the default!
DBB(full and incremental) - should be kept onsite for rapid DB recovery
including restore to the most recent time using a ROLLFORWARD log. I prefer
to do these DBB to a device of type FILE. This allows for much faster
backups and restores. Furthermore, I can schedule a full once a week and
incrementals the rest of the week with no penalty on the restore time for
multiple volumes since they are all coming from disk.
This methodology offers a few more not so obvious advantages, you could
easily schedule multiple DBB incrementals a day thus reducing the size
requirement of you LOG. Also, if you use DEFine DBBackuptrigger you can set
your triggered backups to go to the same device of type FILE which means in
a triggered event your DBB will take place much faster and a rapidly growing
DB would be less likely to trigger the DB spacetrigger.
Remember when defining your DBBackuptrigger to make sure you specify
NUMINCremental to 32 allowing for as many incrementals as possible between
fulls, again there is no penalty here for multiple volumes since it is going
to a device of type FILE.
BTW, based on your note you were doing DBSNAPSHOT's daily which takes as
much space as a DBB full does. If you switch to the method described above,
you will use far less space on disk since you will be doing mostly
incremental backups of the DB.
If you are anyone else has any questions about this please feel free to
contact me either by this list or send me email directly.
--
Regards,
Mark D. Rodriguez
President MDR Consulting, Inc.
============================================================================
===
MDR Consulting
The very best in Technical Training and Consulting.
IBM Advanced Business Partner
SAIR Linux and GNU Authorized Center for Education IBM Certified Advanced
Technical Expert, CATE AIX Support and Performance Tuning, RS6000 SP,
TSM/ADSM and Linux Red Hat Certified Engineer, RHCE
============================================================================
===
Johnson, Milton [IT] wrote:
>All,
>
> TSM: Storage Management Server for AIX-RS/6000 - Version 4,
>Release 2, Level 1.7
> OS: AIX 4.3.3 ML 9
>Log Mode: RollForward
> (Upgrade project planned in near future, but that's another
>story)
>
>Everyday I do a full backup of the database to 3590E tape, immediately
>followed by a DBSNAPSHOT to a file on disk. The 3590E tape promptly
>goes offsite. My question is if I experience a loss of the database
>can I then restore from the DBSNAPSHOT and recover to the point of
>failure using the RECOVERY LOG? I would like to avoid the time delay
>of returning the 3590E tape, containing the database backup, from the
vault.
>
>Anyone done this?
>
>Thanks,
>H. Milton Johnson
>UNIX Systems Administrator - USCC San Antonio, TX
>Email: milton.johnson AT citigroup DOT com
>
>
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