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Home -> Community -> Mailing Lists -> Oracle-L -> RE: RAC or Oracle Fail Safe
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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-----
From: ml-errors_at_fatcity.com [mailto:ml-errors_at_fatcity.com] 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
-- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Hussain Ahmed Qadri INET: hussain_at_skm.org.pk Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). ------=_NextPart_000_01D1_01C34C4E.70D28230 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printableReceived on Thu Jul 17 2003 - 01:30:26 CDT
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<P><FONT SIZE=3D2>Hi Hussain !<BR>
<BR>
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).<BR>
<BR>
RAC can give "Transparent Application Failover" TAF which is = out of consideration in OFS.<BR>
<BR>
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.<BR>
<BR>
Of course both the systems are screwed when your (shared) storage system = is down ;-)<BR>
<BR>
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.<BR>
<BR>
So you are the best judge to decide now ;-)<BR>
<BR>
Just my .2 c<BR>
<BR>
Regards,<BR> Rajesh<BR>
<BR>
<BR>
-----Original Message-----<BR> From: ml-errors_at_fatcity.com [<A = HREF=3D"mailto:ml-errors_at_fatcity.com">mailto:ml-errors_at_fatcity.com</A>]&n= bsp; On Behalf Of Hussain Ahmed Qadri<BR> Sent: Wednesday, July 16, 2003 8:44 PM<BR> To: Multiple recipients of list ORACLE-L<BR> Subject: RAC or Oracle Fail = Safe<BR>
<BR>
Hello all,<BR>
<BR>
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?<BR> 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?<BR> Can any one explain the benefits of using RAC over Oracle Fail Safe, or = vice versa.<BR>
<BR>
Regards,<BR>
<BR>
Hussain<BR>
<BR>
DBA SKMCH&RC<BR>
<BR>
--<BR> Please see the official ORACLE-L FAQ: <A = HREF=3D"http://www.orafaq.net">http://www.orafaq.net</A><BR> --<BR> Author: Hussain Ahmed Qadri<BR> INET: hussain_at_skm.org.pk<BR>
<BR>
Fat City Network Services -- 858-538-5051 <A = HREF=3D"http://www.fatcity.com">http://www.fatcity.com</A><BR> San Diego, California -- = Mailing list and web hosting services<BR> ---------------------------------------------------------------------<BR>= To REMOVE yourself from this mailing list, send an E-Mail message<BR> to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in<BR> the message BODY, include a line containing: UNSUB ORACLE-L<BR> (or the name of mailing list you want to be removed from). You =
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