Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> c.d.o.server -> Re: Physical layout of a DB in RAC environment

Re: Physical layout of a DB in RAC environment

From: Roman Klesel <rupa_at_firemail.de>
Date: Fri, 30 Jan 2004 08:10:28 +0100
Message-ID: <bvd01u$tp5$1@ork.noris.net>

> Roman,
>
> Do you get to keep a backup set on something other than the T1 units?
> (and I don't mean tape).

I don't really understand what you mean here. We do an RMAN Backup to a NFS mounted Filesytem (another point that I'm very suspicious about.

Otherwise no. Everything live and shadow DB resides on different partitions/RAW devices on the 2 T1s which are software mirrored.

> use at least 4 redo log groups, with at least 2 members per group.
> size the logs so that the log switches co-incide with your recovery
> objectives.

That's the case here.

> If you want a log switch every 60 minutes and all of your transactions
> occur during an 8am to 6pm window, then you could roughly estimate
> your log size from:
>
> select to_char(completion_time,'Day HH24') day_hour, count(1),
> trunc(sum(blocks*block_size)/1048576) mb,
> round(trunc(sum(blocks*block_size)/1048576)/count(1),2) avg_log
> from v$archived_log
> where substr(to_char(completion_time,'Day'),1,1)!='S'
> and to_char(completion_time,'HH24') between '08' and '18'
> group by to_char(completion_time,'Day HH24')
> /

Thanks I will use this for optimisation. Until now I was examining the ceckpionts written to the alertfile in order to calculate the frequency of the log switches.

>
> and set the parameter archive_lag_target to the switch interval in
> seconds (e.g. 3600).

Thanks I was allready looking for the cause of the log switches every 30 min.

I'm quite surprised that the idea to just dump everything into a black box is that much accepted. I'm coming from the SAP scene and the performace people there still totally doom this concept. Especially putting Redolog files on such a box. They just hate RAID5.

Roman Received on Fri Jan 30 2004 - 01:10:28 CST

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US