Re: Oracle and High Availiability Software

My experience is with Veritas. Basically the Oracle executables (yes, only one copy is needed) should be installed on the shared disk array, with two identical machines (in our case, Sun E4500s) with the same OS (Solaris 2.6) and partitions.

Veritas cluster software are configured to monitor critical Oracle processes, eg SMON, PMON, DBWR, listener, etc. In the event of any one of them goes down, it will dismount the file system on the primary node, and mount it on the secondary node, and restart the instance.

It works fairly well with us, until this foreverly demanding and unforgiving DBA (aka ME) looking at the mounting cost of Veritas, shared disk array, and basically a big white whale (E4500) sitting there doing nothing but waiting for some distaster to happen.

My understanding is that OPS (Oracle Parallel Server) can be a failover solution, but that is not its primary mission, and you shouldn't reverse engineer a system to use OPS, you should have OPS in your system and database design from the ground up. Otherwise, the various instances will incur unnecessary locking and/or paging.

My question is: Has any one of you guys out there tried using Oracle's Advanced Replication (Multimaster Replication) as a failover solution? Any got'chas? Any satisfied customers? Or am I way off the target here?

Michael

• Original Message ----- From: "Steve Parker" <steve.parker_at_lis.co.uk> To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Monday, May 08, 2000 10:25 AM Subject: Oracle and High Availiability Software

> Dear All,
>
> Consider High Availability (HA) Oracle systems, i.e UNIX and
MC/ServiceGuard
> / TruCluster / HACMP etc
> where the Oracle database and binaries are held on a 'highly resilient'
> shared disk array which can be
> accessed from 2 or more servers.
>
> When either the HA Service providing Oracle is gracefully 'bounced' from
one
> server to the other, or is restarted on an alternate server due to the
main
> server
> crashing etc, is it true to state that only one server at any one time is
> accessing
> ( or can access ) the Oracle database.
>
> Oracle parallel server is NOT being used !
>
> In all cases, 'simple' scripts are used by the HA Service to stop and
start
> Oracle,
> which normally mimic what an operator would do anyway.
>
> I would have thought that 2 sets of binaries accessing the same database
> would have disatrous consequences. I'm sure that under HA, access
> to the datafiles would be strictly controlled to only allow the
> primary server to 'see' them.
>
>
> Any thought / experience / comments please .....
>
>
>
> Thanks
>
>
> Steve Parker
> Technical Consultant
> LIS
>
>
> --
> Author: Steve Parker
> INET: steve.parker_at_lis.co.uk
>
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Received on Tue May 09 2000 - 07:00:16 CDT