I agree with the multiplexing, although there is that interesting contradiction that you multiplex
the redo to ensure that "external" corruption (controller, disk, et al) don't hurt you, but then
store the archived redo (which is just as important) on the same gear, and "99%" of the time,
people rely purely on hardware/software mirroring for these.
Cheers
Connor
- Richard Foote <richard.foote_at_bigpond.com> wrote:
> Hi David
>
> Disagree.
>
> There are 3 things you need to fully recover an Oracle database. A complete
> backup, all the redo logs since the backup and a DBA who know what there're
> doing. Relying on hardware mirroring to protect your "precious" redo logs is
> a risky business as it does not protect you from many possible failure
> scenarios (disk controller failure/corruption, single LGWR write corruption,
> accidental deletion, etc.). Therefore, it can potentially compromise the
> 2nd criteria and put into question the 3rd.
>
> Any database review that does not include multiple redo log members gets a
> (not so little) cross IMHO.
>
> Cheers
>
> Richard
> ----- Original Message -----
> From: "David Wagoner" <dwagoner_at_arsenaldigital.com>
> To: "ORACLE-L (E-mail)" <oracle-l_at_freelists.org>
> Sent: Wednesday, November 24, 2004 1:46 AM
> Subject: Multiplex Redo Logs with Mirrored Disks?
>
>
> Is there any need to multiplex redo logs with mirrored disks (e.g., RAID-1
> or RAID-1+0)?
> Example- Oracle recommends multiplexing redo logs on separate disks, like
> redo01a.log on Disk1 and redo01b.log on Disk2, etc.
>
> However, now that mirrored disks are in common use with RAID-1+0, RAID-1,
> etc. it seems that sufficient protection is in place to use only a single
> copy of each redo log. This would also provide the benefit of reduced disk
> I/O to write redo information to disk.
>
> Anyone disagree?
>
>
> Best regards,
>
> David B. Wagoner
> Database Administrator
>
>
>
>
> --
> http://www.freelists.org/webpage/oracle-l
>
>
> --
> http://www.freelists.org/webpage/oracle-l
>
Connor McDonald
Co-author: "Mastering Oracle PL/SQL - Practical Solutions"
ISBN: 1590592174
web:
http://www.oracledba.co.uk
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Received on Tue Nov 23 2004 - 20:10:33 CST
