[mythtv-users] Backing up mysql database.

Jay R. Ashworth jra at baylink.com
Sun Sep 9 15:58:47 UTC 2007

On Sun, Sep 09, 2007 at 08:08:26AM -0400, Marc wrote:
> > Theoretically, I should never need it considering both my frontend and
> > backend mirrored OS drives.
> Not true. Mirroring saves you from hardware failure in one drive. It 
> doesn't save you from software or human error. A failed upgrade could 
> theoretically trash your database. Having historical archives is good 
> insurance against that.

This reminds me of a *lovely* story told by Philip Greenspun in his
Database Backed Websites book, about "the Oracle studs at Mass General

They had a big supermini, with hardware SCSI mirroring, and *three
racks of drives*.  See, you couldn't hot-backup Oracle in those days,
so they had to come up with *something*, since they were a hospital,
and not allowed downtime.

They had a spare, smaller, machine in the computer room.

The main machine's SCSI A went to a rack of drives.

The main machine's SCSI B, and the secondary machine's SCSI interface,
hit a crossover switch, the other side of which went to two racks of

When it was backup time, they racked the big mechanical switch, booted
the secondary, and while the primary was rebuilding it's mirror, the
secondary played back it's binlogs, then shut down Oracle and did the

Next day, same dance in reverse.

Insanely clever, I've always thought.

-- jra
Jay R. Ashworth                   Baylink                      jra at baylink.com
Designer                     The Things I Think                       RFC 2100
Ashworth & Associates     http://baylink.pitas.com                     '87 e24
St Petersburg FL USA      http://photo.imageinc.us             +1 727 647 1274

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