ADSM-L

Re: Client and AIX mirrored disks...

2001-10-23 16:55:28
Subject: Re: Client and AIX mirrored disks...
From: Robin Sharpe <Robin_Sharpe AT BERLEX DOT COM>
Date: Tue, 23 Oct 2001 16:52:28 -0400
Thomas,

I'd love to see that script, if you're willing to share!   :)

Robin Sharpe
Berlex Laboratories



                    Thomas Denier
                    <Thomas.Denier@MAI
                    L.TJU.EDU>         To:    ADSM-L AT VM.MARIST DOT EDU
                                       cc:    (bcc: Robin Sharpe/WA/USR/SHG)
                    10/23/01 03:50 PM  Subject:
                    Please respond to         Re: Client and AIX mirrored 
disks...
                    "ADSM: Dist Stor
                    Manager"







Quoting "Greatbanks, Stephen P" <stephen.greatbanks AT EDS DOT COM>:

> 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.

We have done this kind of thing on HP-UX by having the TSM central
scheduler run a Perl script rather than an incremental backup. The
Perl script provides the intelligence that is missing from TSM. The
script splits mirrors, mounts them as phantoms, builds a list of
file systems to back up, invokes dsmc to do the backup, unmounts
the phantoms, and rejoins the mirrors. The list of file systems
passed to dsmc includes the phantoms but not the corresponding
production file systems. The list also includes file systems that
are not involved in the broken mirror scheme, such as /, /var, and
/usr.
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