Re: Log file I/O throughput

Norman Dunbar <Norman.Dunbar_at_lfs.co.uk> wrote in message news:<E2F6A70FE45242488C865C3BC1245DA7040E8DC0_at_lnewton.leeds.lfs.co.uk>...
> >> Or
> >> to drop the mirrored copy altogether since redundancy in built into
> >> the I/O subsystem (Hitachi S.A.N).
>
> Picture this, Oracle mirrors your logfiles and an operator, in a moment
> of weakness, deletes one of the mirrored copies. The remaining mirrors
> will not be deleted.
>
> Now, run the same thought experiment again, but this time with OS (or
> SAN) mirroring, this time what happens when one of the mirrored copies
> gets deleted - the mirrors are also deleted leaving you with nothing.
>
> Same applies to control files - don't let the OS mirror than unless
> Oracle is also mirroring.

Hi, Norman,

I know some people don't like it. But using one log member per group when you have good hardware redundancy is actually good practice. It saves on log file single write time (when AIO is enabled). I remember Steve Adams recommended it (or could be somebody else?) and also noticed a person working at BMC on the OAUG mailing list was doing that. I've been doing that for some time. You just have to be a little more careful in deleting files.

Yong Huang Received on Tue Aug 12 2003 - 22:23:12 CDT