ADSM-L

Re: Client and AIX mirrored disks...

2001-10-23 20:12:30
Subject: Re: Client and AIX mirrored disks...
From: Steve Harris <STEVE_HARRIS AT HEALTH.QLD.GOV DOT AU>
Date: Wed, 24 Oct 2001 09:51:04 +1000
The ability to do split mirror backups of AIX JFS came in at AIX 4.3.3 see 
chapter 5 of the AIX 4.3 Differenences redbook. Steve Greatbanks - you should 
note that sysback is not required.

Steve Harris
AIX and TSM Admin
Queensland Health, Brisbane Australia

>>> Zlatko Krastev/ACIT <acit AT ATTGLOBAL DOT NET> 23/10/2001 18:40:33 >>>
The only way to "break the mirror" and access both copies in AIX known to
me is to pull the disk and put it into another machine importing the VG.
Otherwise the mirror is still transparent to you through AIX APIs and
tools.
In Windows NT you can break the mirror of a partition and late the copy can
be assigned another letter. At least I am not familiar does such method
exist in AIX.
Are you files so intensively accessed (if yes by what application) and
aren't you satisfied by "shared static" and "shared dynamic" serialization
options?

Zlatko Krastev
IT Consultant





"Greatbanks, Stephen P" <stephen.greatbanks AT EDS DOT COM> on 23.10.2001 
03:11:44
Please respond to "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
To: ADSM-L AT VM.MARIST DOT EDU 
cc:

Subject: Re: Client and AIX mirrored disks...

Zlatko,
 Thanks for the information. I do realise that the AIX mirroring is
totally transparent from the user (and TSM) point of view. That is not
really my question though. The current backup procedure is (roughly)

(i) Stop all clients using the filesystems
(ii) Do a mksysb
(iii) Break off one of the mirror copies
(iv) Re-mount the broken mirror copies as phantoms that we backup
(v) Allow clients to access disks
(vi) Backup the broken mirrors
(vii) Re-sync the mirrors

The reason we do this is to minimise the downtime for the machine
and to allow a backup to continue whilst clients can use the filesystems.
Effectively we are taking a point-in-time snapshot of the filesystems.
I guess that what I was asking is whether there is anything in the TSM
client (in terms of smarts) to allow it to do something similar.
Am I right in thinking that the client will rely on the filesystem not
changing underneath it?


If we cannot, then we will just have to wear the downtime.

Thanks for that,

Steve Greatbanks

ps - You are of course right about varyon/varyoff working at the VG, rather
than the LV level.

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