Clarification (Primary/Mirror chuncks)
Question: if a mirrored primary chunk goes down and the server runs on the mirror for a while, does the primary get resynchronised automatically when brought back? Answer from several respondents: yes, automatically. Once the chunk is marked up again (onspaces -s <space> -p <path> -o <offset> -O), IDS verifies and rebuilds it from the active mirror, so no restore is needed. The resync time depends on disk size, is seamless to users who can keep writing, and no noticeable performance hit was reported; mirroring is even a common way to migrate data to a new drive.
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Hi all, Can someone please explain to me what happens when a mirrored primary dbspace is marked as down, and you start operating with the mirror chunk for a while, then you bring the primary chunk back online, will the data get synchronized from the mirror chunk to the primary chunk automatically or you need to run some process to do this? Paul
It will automagically re-synch. j. -----Original Message----- From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org]On Behalf Of PAUL GATHOGO Sent: Monday, February 05, 2007 1:38 AM To: ids@iiug.org Subject: Clarification (Primary/Mirror chuncks) [8345] Hi all, Can someone please explain to me what happens when a mirrored primary dbspace is marked as down, and you start operating with the mirror chunk for a while, then you bring the primary chunk back online, will the data get synchronized from the mirror chunk to the primary chunk automatically or you need to run some process to do this? Paul **************************************************************************** *** Forum Note: Use "Reply" to post a response in the discussion forum.
Automagically :), Any idea on how long this re-sync process would take?, and what will be the state of the DB Server at that point, i.e will the users be able to write on the DB? Thanks
It's considered good form to quote at least part of the posting you are responding to. Have no idea what you're asking. Art S. Kagel ----- Original Message ----- From: Paul Gathogo <ids@iiug.org> At: 2/05 7:05:15 Automagically :), Any idea on how long this re-sync process would take?, and what will be the state of the DB Server at that point, i.e will the users be able to write on the DB? Thanks ******************************************************************************* Forum Note: Use "Reply" to post a response in the discussion forum.
Just resyncs by magic, its automatic Paul Watson Tel: +44 1414161772 Mob: +44 7818003457 Web: www.oninit.com Failure is not as frightening as regret. Attend IDUG 2007 San Jose, North America May 6-10, 2007 Visit http://www.iiug.org/conf for more information. > -----Original Message----- > From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On > Behalf Of PAUL GATHOGO > Sent: 05 February 2007 00:38 > To: ids@iiug.org > Subject: Clarification (Primary/Mirror chuncks) [8345] > > Hi all, > > Can someone please explain to me what happens when a mirrored > primary dbspace is marked as down, and you start operating > with the mirror chunk for a while, then you bring the primary > chunk back online, will the data get synchronized from the > mirror chunk to the primary chunk automatically or you need > to run some process to do this? > > Paul > > > ************************************************************** > ***************** > Forum Note: Use "Reply" to post a response in the > discussion forum.
Paul-
That is exactly correct. When the down device is marked "up"
(onspaces -s <spacename> -p <path> -o <offset> -O), IDS verifies the
space and then rebuilds it from the active secondary device. This
allows you to replace a primary device without a restore.
--EEM
-----Original Message-----
From: ids-bounces@iiug.org [mailto:ids-bounces@iiug.org] On Behalf Of
PAUL GATHOGO
Sent: Monday, February 05, 2007 12:38 AM
To: ids@iiug.org
Subject: Clarification (Primary/Mirror chuncks) [8345]
Hi all,
Can someone please explain to me what happens when a mirrored primary
dbspace
is marked as down, and you start operating with the mirror chunk for a
while,
then you bring the primary chunk back online, will the data get
synchronized
from the mirror chunk to the primary chunk automatically or you need to
run
some process to do this?
Paul
************************************************************************
*******
Forum Note: Use "Reply" to post a response in the discussion forum.
How long depends on the size of your disk, but it is totally seamless to the
users. At one point we had a system which kept losing it's primary drive. It
was so seamless, that we only noticed that the drive was down by checking
onstat -d or the logfile. One of the accepted ways to move data from one driveto another under informix is to mirror an old drive to a new drive and let the
engine do the work.
I can't speak to performance impact, I've never noted one.
j.
>From: PAUL GATHOGO <pgathogo@gmail.com>
>Date: 2007/02/05 Mon AM 06:04:56 CST
>To: ids@iiug.org
>Subject: Re: RE: Clarification (Primary/Mirror chuncks) [8348]
>Automagically :), Any idea on how long this re-sync process would take?, and
>what will be the state of the DB Server at that point, i.e will the users be
>able to write on the DB?
>
>Thanks
>
>
>*******************************************************************************
> Forum Note: Use "Reply" to post a response in the discussion forum.
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