Hi Rajesh,
Thanks for
the detailed reply and I really appreciate that. Certain clarifications.
1.
With reference to what you said about using both the
nodes, you meant that we can install another database (lets say for reporting purpose)
or/and also 9iAS on one node and our main production database on the other
2.
Incase of OFS, the database service fails over from
one node to the other, and then it starts, but it is automatic, right?
3.
When you talk about Resources and that they can’t be
shared, you are not referring to the shared storage vault (we are using DAS –
Direct Attached Storage) because that has to be at least available to both the
servers. And when the database fails over from one server to the other, and it
starts its services on the other server, then the obviously that other server
will make use of the DAS on which reside our datafiles.
4.
RAC costs roughly 20k$ per CPU and it doesn’t come
bundled with Oracle 9i License? (For confirmation purposes)
5.
From various mails I gather that OFS is basically a
safe bet, if the hardware supporting is good. And if, God-forbid, one server
goes down then the only time lapse is the time it takes to start the services
on the other server.
6.
The transactions taking place at the time when main
server goes down will be lost, I mean it will give a feeling of hung database
or some other error.
Thanks in
advance, and waiting for your reply.
Regards,
Hussain
-----Original
Message-----
From: RAJESH DAYAL [mailto:[EMAIL PROTECTED]
Sent: Thursday, July 17, 2003
12:30 PM
To: Multiple recipients of list
ORACLE-L
Subject: RE: RAC or Oracle Fail
Safe
Hi Hussain !
RAC can have Active-Active or Active-Passive combination for two nodes. While
OFS can't give you Active-Active combination of two nodes. Basically a resource
sharing is not possible in Oracle Fail safe so one resource can be used by only
one node at one point of time. ( Resource means Hard Disk Space, Oracle
Service, Listener etc).
RAC can give "Transparent Application Failover" TAF which is out of
consideration in OFS.
In case of node failure on RAC System, the user will just need to attempt
relogin and he will be connected _immediately_ to another surviving instance (
If tnsnames.ora is configured properly). While there is a significant amount of
delay in case of OFS, the Database service has to failover from one node to
another node and this may take it's own _sweet_ amount of time based on amount
and type of activity being performed on the database.
Of course both the systems are screwed when your (shared) storage system is
down ;-)
Lastly why would someone want to use only 1 out of 2 nodes when it is possible
to use both the nodes? One possible answer is that, on one node you configure
One server (say 9iAS) and on another node you configure database. Then under
normal condition they will run on their respective nodes and when one fails
they would switch-over to the surviving node. So your performance may suffer
for the time during which any node is down.
So you are the best judge to decide now ;-)
Just my .2 c
Regards,
Rajesh
-----Original Message-----
HREF="" PROTECTED]">mailto:[EMAIL PROTECTED]
On Behalf Of Hussain Ahmed Qadri
Sent: Wednesday, July 16, 2003 8:44 PM
To: Multiple recipients of list ORACLE-L
Subject: RAC or Oracle Fail Safe
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
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