IDS Forum

RE: snapshots of db disks on SAN

Posted By: Clifford Burton
Date: Monday, 23 October 2006, at 6:29 p.m.

In Response To: RE: snapshots of db disks on SAN (Bruce Simms)

The length of time for the 'block' of the instance varies, you'll need
trial and error to discover the optimal result. You'll find the more
LUNs the instance uses the longer the time: In addition factors like the
SAN flare code versions and logging mode of the database all play their
parts.

I quite envy Bruce, who can get the round trip done in less than four
seconds :) mine take around twelve seconds.

-----Original Message-----
From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of
Bruce Simms
Sent: Tuesday, 24 October 2006 00:38
To: ids@iiug.org
Subject: RE: snapshots of db disks on SAN [7663]

Bob,

We issue the block in a shell upon the return from the block we issue
the breaking of the mirror followed by the unblock. This whole action
takes less tan 4 seconds ton our systems.

*** Please note the new address and phone number below.

Bruce Simms
Data Base Services
TALX Corporation
1850 Borman Court
St. Louis, MO 63146

Phone (314) 214-7703
FAX (314) 983-3238
bsimms@talx.com

-----Original Message-----
From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of
Robert Roussey(MIS)
Sent: Monday, October 23, 2006 9:35 AM
To: ids@iiug.org
Subject: RE: snapshots of db disks on SAN [7662]

How long do you have to do the block?

Bob Roussey
Robert.Roussey@SpiritAir.com

-----Original Message-----
From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of
Bruce Simms
Sent: Thursday, October 19, 2006 11:09 AM
To: ids@iiug.org
Subject: RE: snapshots of db disks on SAN [7651]

We use the EMC with Informix9.4.fc5 on Solaris and sucessfully use
mirror copies. We sync up the mirrors between two EMC units and once in
sync we issue the onmode -g block then break the connection then issue
the onmode -c unblock. We have used thes copies in test but also as our
offsite DR point.

-----Original Message-----
From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of
George Palmer
Sent: Thursday, October 19, 2006 9:45 AM
To: ids@iiug.org
Subject: RE: snapshots of db disks on SAN [7650]

You will need to read the manual about "external backups" You have the
ability to use a blocking check point "onmode -c block" and once the
snap is complete you issue the "onmode -c unblock"

This will let the DBSEREVER know there is an external backup (there are
directions to do external backup and restore in the manuals.

We use the external backup to bring up a secondary server (for testing
and read only purposes on a very large Operation Data Store. (not on
10.00 though on an earlier release) We also archive the secondary to
tape (the secondary is not part of HDR or CDR and gets overwritten daily

and would the company would like the ability to restore to a given data
and time from more then a day ago if we need to. Local logs can be
replayed as part of the "external" restore.

Also onstat -g arc shows when the last external (or regular) archive has

been taken.

NOTE of importance. If the snap is not completed before the next check
point there will be a period of time when no writes/updates will be
allowed.
The lock up will be equivalent to a very long checkpoint.

George

-----Original Message-----
From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of
ROBERT ROUSSEY
Sent: Thursday, October 19, 2006 7:17 AM
To: ids@iiug.org
Subject: snapshots of db disks on SAN [7648]

IDS 10.00.UC4 / RedHat AS 3.

We are moving to a configuration with all of our db disks on a SAN
(Dell/EMC?). I was told that the SAN itself does 'snapshots' to other
disks as
often as we configure it. My mgmt spec'ing and ordering the equipment
was told
that these snapshots to a mirrored SAN should be fine to bring up the db

if
the primary SAN goes down. We currently use ontape for full backups. I'm

concerned that the SAN snapshots don't take into consideration the
checkpoint
and timestamp info that ontape does. Does anyone else have their db
disks on a
SAN and done a successful failover / switch-over to a backup SAN *with*
the db
running with a full load; ie: without quiescing the db?

TIA

Bob Roussey
robert.roussey@spiritair.com

************************************************************************

*******
Forum Note: Use "Reply" to post a response in the discussion forum.

************************************************************************

*******
Forum Note: Use "Reply" to post a response in the discussion forum.

************************************************************************

*******
Forum Note: Use "Reply" to post a response in the discussion forum.

************************************************************************

*******
Forum Note: Use "Reply" to post a response in the discussion forum.

************************************************************************
*******
Forum Note: Use "Reply" to post a response in the discussion forum.

*******************************************************************
Everything about this email and its attachments, including potentially confidential components, is only for the eyes and ears of the persons to whom it has been addressed (i.e. the persons whose names appear in the "To" section of the email; however, those listed in sections "CC" and "BCC" may also consider themselves included in the group whose eyes and ears this email is for.). In the event that no physical, emotional or spiritual resemblance can be made between you and the intended recipients, you have been mistakenly or deliberately omitted from the email, someone has given it to you, or you have nicked it. If you're not supposed to have access to this email, please delete it, destroy it and deprive others from it. Oh, and let us know when you are done.
*******************************************************************

Messages In This Thread

• snapshots of db disks on SAN
  ROBERT ROUSSEY -- Thursday, 19 October 2006, at 10:16 a.m.
  • Re: snapshots of db disks on SAN
    ART KAGEL, BLOOMBERG/ 731 LEXIN -- Thursday, 19 October 2006, at 10:25 a.m.
  • RE: snapshots of db disks on SAN
    George Palmer -- Thursday, 19 October 2006, at 10:44 a.m.
    • RE: snapshots of db disks on SAN
      Bruce Simms -- Thursday, 19 October 2006, at 11:08 a.m.
      • RE: snapshots of db disks on SAN
        Robert Roussey\(MIS\) -- Monday, 23 October 2006, at 10:35 a.m.
        • RE: snapshots of db disks on SAN
          Bruce Simms -- Monday, 23 October 2006, at 10:38 a.m.
          • RE: snapshots of db disks on SAN
            Clifford Burton -- Monday, 23 October 2006, at 6:29 p.m.
            • RE: snapshots of db disks on SAN
              Bruce Simms -- Tuesday, 24 October 2006, at 8:13 a.m.

IDS Forum is maintained by Administrator with WebBBS 5.12.