RE: RAC or Oracle Fail Safe

Thank you to all those who replied and who intend to reply to this one :)

We are using Dell PE4600 servers. My concern was that I read it somewhere that if one of the node goes down, then the clients have to restart the application to log in again to the database, is that true? And is it any different on RAC? We have the licensed RAC and Oracle Fail Safe CDs, so that is not an issue. I also believe that setting up RAC is more complex, so we wanted to confirm that if Fail Safe gives us HA, 24x7, and any change in node shifting (when active is down, passive becomes active) is transparent to the user then we should go for Fail safe. By the way, we intend to keep cluster settings of ACTIVE and PASSIVE, is there any issue regarding this?

Tanel Poder: you said that, " in event of failure you can start up instance on another node that will mount, recover and open the database." Doesn't the second node automatically take over? And this means that the user has to log in again, do I get it right?

Best Regards,

Hussain

-----Original Message-----
From: Tanel Poder [mailto:tanel.poder.003_at_mail.ee] Sent: Wednesday, July 16, 2003 10:44 PM
To: Multiple recipients of list ORACLE-L Subject: Re: RAC or Oracle Fail Safe

Hi!

RAC - One database, two (or more) instances servicing it concurrently. If one node crashes, second one starts recovering, your uncommitted transactions and session state variables (package variables) on failed instance are lost.

FailSafe - One database, one instance servicing it at any time, in event of failure you can start up instance on another node that will mount, recover and open the database.

With RAC you can have some kind of transparent failover which is able to reexecute your queries on survived instance, but AFAIK for uncommitted transaction survivability your app has to be coded to support it. Also, with RAC you may scale your system up to support more users in some cases.

RAC is additional $20k per CPU, FailSafe comes with EE, I believe.

Tanel.

• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: Wednesday, July 16, 2003 7:44 PM

> Hello all,
>
> We have setup a Microsoft Cluster Server (MSCS) cluster, with two nodes,
using W2K, and now are in the process of deploying Oracle 9i on it. For the purpose of high availability (HA), we are deliberating on setting up either RAC or Oracle Fail Safe. The confusion is over the fact that if we get HA with oracle Fail Safe, i.e. if one node is down due to any problem, then the other takes over, then can we do without RAC?
> Which of these two is more transparent to the user, i.e. which will take
less time to shift the load from one node (server) to the other node?
> Can any one explain the benefits of using RAC over Oracle Fail Safe, or
vice versa.
>
> Regards,
>
> Hussain
>
> DBA SKMCH&RC
>
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
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> Author: Hussain Ahmed Qadri
> INET: hussain_at_skm.org.pk
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--
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--
Author: Tanel Poder
  INET: tanel.poder.003_at_mail.ee

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