Re: Guaranteeing Full Database Recovery on a 2 Disk Server

In article <3A12B74E.D848030B_at_iel.ie>,
  Mark Patterson <mpatterson_at_iel.ie> wrote:
>
> Hi,
>
> I'm installing a database on a server that currently has only two
> physical disks.
> The system will be going live very soon (sooner than more disks can be
> ordered and delivered!) and I just want to ensure that my database
> structure will guarantee a full database recovery should one of the
> disks fail.
>
> I accept that performance won't be exactly ideal but reliability is of
> greater concern in the short term.
> The database is in achivelog mode and fully backed up to tape nightly.
>
> The database is structured as follows (TS = tablespace):
>
> DISK A:
> System TS
> Data TS
> Index TS
> Temp TS
> Rollback TS
> Contol file A
> Redo Group1 Member 1A
> Redo Group2 Member 2A
>
> DISK B:
> Contol file B
> Redo Group1 Member 1B
> Redo Group2 Member 2B
> Archived Redo Logs
>
> I've based this on the assumption that if "DISK A" fails we can
 recover
> the nightly backup to a new disk (I know we don't have one yet but
> here's hoping it arrives before we have a crash!!) and roll forward
> using the archived redo logs and if "DISK B" fails we'll be fine until
> we attempt a log switch in which case the database will freeze.
> Both these scenarios are fine as I can accept delay and downtime while
> we look for replacement disks but I need to guanantee that should
 either
> fail we can fully recover.
>
> Thanks
> Mark.
>
> --------------949D89B2AB384EF64256331D
>

Looks OK.

Some systems support writing the archived redo logs straight to tape so if a tape drive can be dedicated to this task and you have at least two drives so you can write a hot backup to tape at the same time, you could potentially run the database on both disks if performance is an issue.

Tape management is an issue in itself though.

--
Mark D. Powell  -- The only advice that counts is the advice that
 you follow so follow your own advice --


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