Yes, as Ken stated below, our DB mirrors (mirrored via adsm) have
     provided us uninterrupted service for about 3-4 years now.

     Actually long ago there was a case where we lost a drive which
     contained a DB vol and it wasn't noticed for about 3 days (yes, our
     monitoring has improved since then)
     AND
     another time I was cleaning up "stuff" and by accident deleted a
     functioning DB vol (talk about panic!) but the mirror kept things
     running smooth with no interruptions and I corrected my mistake FAST.

     Dwight


______________________________ Reply Separator _________________________________
Subject: Re: DB mirroring vs. RAID
Author:  ken x. sparks at tulsa,itss
Date:    4/21/99 5:34 PM


     Shouldn't the mirror allow you to continue without interruption?  Ours
     do.  You just replace the failed drive and resync the filesystem.


______________________________ Reply Separator _________________________________
Subject: Re: DB mirroring vs. RAID
Author:  MRemeta (MRemeta AT SELIGMANDATA DOT COM) at unix,mime
Date:    4/21/99 2:08 PM


So if it was on a RAID 5 set and you had lost one disk, your database would
have still been intact and you would have had 0 hours of down time (assuming
the RAID 5 worked the way it was suppose to).
Sounds like a pretty good case for RAID 5 instead of mirroring.



> -----Original Message-----
> From: James, Ron [SMTP:Rjames AT ATSGROUP DOT COM]
> Sent: Wednesday, April 21, 1999 1:09 PM
> To:   ADSM-L AT VM.MARIST DOT EDU
> Subject:      Re: DB mirroring vs. RAID
>
> I stand caught - No, Mine is not a Raid set - I had a limited number of
> drives that I could install so I maximized the total drive space for pools
> and db logs - Certainly if space permits - go for it - I wasn't willing to
> lose 1/n of my drive space for Raid 5. I migrate to tape and a copy pool
> immediately after completing my backups. It's a personal comfort issue -
> I'm
> comfortable with the setup that I have - you may want the additional fault
> tolerance.
>
> Ron
>
>                 -----Original Message-----
>                 From:   Remeta, Mark [mailto:MRemeta AT SELIGMANDATA DOT COM]
>                 Sent:   Wednesday, April 21, 1999 8:35 AM
>                 To:     ADSM-L AT VM.MARIST DOT EDU
>                 Subject:        Re: DB mirroring vs. RAID
>
>                 Yes but you did not answer Reinhard's question. Was the
> 'primary disk' a
>                 RAID 5 set?
>
>
>                 > -----Original Message-----
>                 > From: James, Ron [SMTP:Rjames AT ATSGROUP DOT COM]
>                 > Sent: Wednesday, April 21, 1999 10:00 AM
>                 > To:   ADSM-L AT VM.MARIST DOT EDU
>                 > Subject:      Re: DB mirroring vs. RAID
>                 >
>                 > Mirroring saved my butt once - I lost the primary disk -
> I
> replaced the
>                 > disk
>                 > and with the help of Kelly Lipp at SSSI we restored the
> server from the
>                 > mirrored volume - and was well in under a few hours.
>                 >
>                 > Ron James
>                 > Network Management Specialist
>                 > Premiere Conferencing
>                 >
>                 >                 -----Original Message-----
>                 >                 From:   Reinhard Mersch
> [mailto:mersch AT UNI-MUENSTER DOT DE]
>                 >                 Sent:   Wednesday, April 21, 1999 5:44
> AM
>                 >                 To:     ADSM-L AT VM.MARIST DOT EDU
>                 >                 Subject:        DB mirroring vs. RAID
>                 >
>                 >                 Hi,
>                 >
>                 >                 again I am struggling with my ever
> growing
> ADSM DB, not
>                 > knowing where to
>                 >                 get the additional disk space I need. An
> option would be,
>                 > to
>                 > give up DB
>                 >                 mirroring and rely on RAID5 instead.
>                 >
>                 >                 Since RAID5 protects against
> media/hardware failures, are
>                 > there other
>                 >                 threats, DB mirroring protects against
> and
> RAID5 does not?
>                 > There has been
>                 >                 discussion on this in August 98 and Andy
> Raibeck mentioned
>                 > partial page
>                 >                 writes. But how probable are they? Has
> anybody out there
>                 > ever been in a
>                 >                 situation where DB mirroring (would
> have)
> helped and RAID5
>                 > (would have)
>                 >                 not?
>                 >
>                 >                 Regards
>                 >
>                 >                 --
>                 >                 Reinhard Mersch
> Westfaelische
>                 > Wilhelms-Universitaet
>                 >                 Zentrum fuer Informationsverarbeitung -
> ehemals
>                 > Universitaetsrechenzentrum
>                 >                 Roentgenstrasse 9-13, D-48149 Muenster,
> Germany      Tel:
>                 > +49(251)83-31583
>                 >                 E-Mail: mersch AT uni-muenster DOT de
> Fax:
>                 > +49(251)83-31653