Re: Multiplexing Archive Logs

From: S. F. Lott <slott_at_delphi.com>
Date: 1996/03/21
Message-ID: <31521338.5D7B_at_delphi.com>#1/1


Howard L. Curtis wrote:
>
> Does anyone have any thoughts, comments, issues regarding
> multiplexing the archive logs. Oracle currently multiplexes
> the redo logs to enable fault tolerance, but the archive log
> is still a single point of failure. [snip]

Check the Oracle DBA guide for details, but as I understand it there are several failure modes:
1) server S/W crash. RDBMS recovers from on-line redo logs, never touches archives. We did this just today when we forced a Solaris reboot with two instances running - back on line in 5 min. 2) OS crash - a lot like server s/w crash. 3) media failure. If it had mirrored files - online redo logs, control files and the like, keep running and rebuild the disk while the RDBMS continues. If it had RDBMS data files - now you need archived redo logs and prior backups and everything. For that (rare) eventaulity, put your archived redo logs on a RAID device.

Don't put your regular tablespaces on RAID - although there are pros and cons - we lost performance and couldn't do any tuning any more. Using a sexy RAID as a place to keep redo log archives (and regular backups of data files) seems kind of backwards, but I think it makes sense.

-- 
S. Lott
Consultant, NE Region
CTG
SLOTT_at_DELPHI.COM
S.LOTT_at_CTG.COM
800-992-5350 box 7053
Received on Thu Mar 21 1996 - 00:00:00 CET

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