IDS Forum

RE: Snapshot Backup

Posted By: Konikoff, Robert W Mr CIV US USA AMC
Date: Thursday, 14 April 2011, at 9:42 a.m.

In Response To: Re: Snapshot Backup (Habichtsberg, Reinhard)

We are wrestling with SAN level backup strategies now.

Our next platform:
HP-UX 11.iv3
IDS 11.5

I want transaction level strategy for offsite disaster recovery, but
'management' thinks it costs too much. They are leaning towards SAN copies.

Check me out here... To synthesize this conversation then on SAN level
archiving:

Informix calls SAN level archives an external archive. To do this, you have
to checkpoint the Informix instance and block new transactions from being
written to disk while the SAN copy is being written. Then once the copy is
complete, release the block. This is done as follows:

1. onmode -c block

2. snapshot

3. onmode -c unblock

In this case, the snapshot can be 3rd party software. INFORMIX doesn't do
'snapshots' since they take more space than a level 0 archive. Clones will
copy all of the database's chunks, and even the array spaces that are not
yet allocated to the instance. Vendor products that do database snapshots
may be more efficient in taking only the used space, with minimal overhead,
but that requires product evaluation to determine the overhead and copy
parameters.

Am I tracking?

Thanks...

Rob

-----Original Message-----
From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of
Habichtsberg, Reinhard
Sent: Thursday, April 14, 2011 3:55 AM
To: ids@iiug.org
Subject: Re: Snapshot Backup [23415]

What you are talking about is what I would call a clone. A snapshot in
contrast taken with the means of some of the storage distributors takes
only the space of the administrative overhead. That is minimal. Simply
spoken the snapshot points to the same blocks as the original. Updates
of the original will be only reflected there because the snap blocks
will not be overwritten but new blocks and pointers will be created.
Only the differences between original and snapshot will consume space.

The snapshot can be used as external backup as said by the foreposters.

I have to confess that I have no practical knowledge with that spaceless
snapshots. We will implement a new SAN soon so I had to look into some
features of storage technology of today.

Reinhard.

> -----Original Message-----
> From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of
John
> Miller iii
> Sent: Thursday, April 14, 2011 8:52 AM
> To: ids@iiug.org
> Subject: Re: Snapshot Backup [23414]
>
> Snapshot backup generally consume allot more space than an Informix
> Level 0 backup. This is because Informix understand what is free space
> both inside and outside of tables and does not back this up. That
being
> said there are many fancy disk based snap/flash technologies which
> can do some pretty impressive work.
>
> Yes you can apply logical logs after executing a snapshot backup
> (or as Informix calls it an External Backup)
>
> John F. Miller III
> STSM, Embedability Architect
> miller3@us.ibm.com
> 503-578-5645
> IBM Informix Dynamic Server (IDS)
>
> ids-bounces@iiug.org wrote on 04/13/2011 03:45:21 PM:
>
> > From:
> >
> > "SHAHZAD SALAM KASI" <skasi@i2cinc.com>
> >
> > To:
> >
> > ids@iiug.org
> >
> > Date:
> >
> > 04/13/2011 03:46 PM
> >
> > Subject:
> >
> > Re: Snapshot Backup [23411]
> >
> > Sent by:
> >
> > ids-bounces@iiug.org
> >
> > Thanks for the response.
> >
> > Is Snapshot backup consumes less space than Level-0 backup ?
> > Also, can we apply logs after re-storing using Snapshot backup ?
> >
> > What is the command to take snapshot backup ?
> >
> > Thanks.
> >
> >
> >
>
>
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> >
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>
>
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Messages In This Thread

• Snapshot Backup
  SHAHZAD SALAM KASI -- Wednesday, 13 April 2011, at 5:33 p.m.
  • Re: Snapshot Backup
    Art Kagel -- Wednesday, 13 April 2011, at 6:35 p.m.
    • Re: Snapshot Backup
      SHAHZAD SALAM KASI -- Wednesday, 13 April 2011, at 6:45 p.m.
      • Re: Snapshot Backup
        Madison Pruet -- Wednesday, 13 April 2011, at 6:53 p.m.
      • Re: Snapshot Backup
        Art Kagel -- Wednesday, 13 April 2011, at 7:52 p.m.
      • Re: Snapshot Backup
        John Miller iii -- Thursday, 14 April 2011, at 2:51 a.m.
        • Re: Snapshot Backup
          Habichtsberg, Reinhard -- Thursday, 14 April 2011, at 3:54 a.m.
          • RE: Snapshot Backup
            Konikoff, Robert W Mr CIV US USA AMC -- Thursday, 14 April 2011, at 9:42 a.m.
            • Re: Snapshot Backup
              Art Kagel -- Thursday, 14 April 2011, at 10:09 a.m.
              • Re: Snapshot Backup
                David Zinder -- Thursday, 14 April 2011, at 10:59 a.m.
                • Re: Snapshot Backup
                  Art Kagel -- Thursday, 14 April 2011, at 2:19 p.m.
                  • RE: Snapshot Backup
                    Bruce Simms -- Thursday, 14 April 2011, at 2:53 p.m.
            • RE: Snapshot Backup
              Habichtsberg, Reinhard -- Thursday, 14 April 2011, at 10:39 a.m.
              • RE: Snapshot Backup
                Konikoff, Robert W Mr CIV US USA AMC -- Thursday, 14 April 2011, at 10:49 a.m.
            • RE: Snapshot Backup
              Konikoff, Robert W Mr CIV US USA AMC -- Thursday, 14 April 2011, at 10:44 a.m.
            • Re: Snapshot Backup
              Art Kagel -- Thursday, 14 April 2011, at 10:56 a.m.
              • RE: Snapshot Backup
                Habichtsberg, Reinhard -- Thursday, 14 April 2011, at 11:26 a.m.

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