Whoa, a SAN is non-redundant??? =20 I agree it could still be a SPOF but it certainly is redundant component = wise... =20 I guess you're entitled to your opinion regarding rather RAC provides HA = for the Oracle Instance or not. Keyword here is Instance. RAC provides = HA at the Oracle instance, that does not exclude you from addressing the = other SPOFs in your environment (to what degree your budget = allows)...but if 1 instance in the RAC cluster should go down, there = should be others available to handle the workload... =20 My definition HA for the Oracle instance is really just that there is = minimal downtime should 1 instance in the RAC cluster be unavailable. = What does any other HA clustering solution provide? It simply restarts = the Oracle instance on the standby node... =20 If you have a different definition of HA, well that maybe that's where = we're miscommunicating...=20 =20 ________________________________ From: Jared Still [mailto:jkstill@xxxxxxxxx] Sent: Wed 6/1/2005 5:18 PM To: Khemmanivanh, Somckit Cc: oracle-l@xxxxxxxxxxxxx Subject: Re: Oracle RAC cost justification? HA for the Oracle Instance? You're kidding, right? If you have SPOF, it isn't HA. A non-dedundant disk system is a rather glaring SPOF. On 6/2/05, Khemmanivanh, Somckit <somckit.khemmanivanh@xxxxxxxxxxxxxxxx> = wrote:=20 Well RAC is not the SAN right? RAC is HA for the Oracle Instance. =20 If you're saying the total HA solution involves eliminating all SPOFs, = I'd agree but cost is always a limiting factor in that regard... =20 Thanks!=20 =20 ________________________________ From: Jared Still [mailto:jkstill@xxxxxxxxx]=20 Sent: Wednesday, June 01, 2005 4:04 PM To: Khemmanivanh, Somckit Cc: Vlado Barun; oracle-l@xxxxxxxxxxxxx Subject: Re: Oracle RAC cost justification? =09 =09 =09 On 6/1/05, Khemmanivanh, Somckit = <somckit.khemmanivanh@xxxxxxxxxxxxxxxx> wrote:=20 Let's say we already have Service Guard in house. For new implementations should we go with MCSG or look at RAC? RAC is an HA = and scalability solution (MCSG is purely HA). I'm trying to get a good =09 RAC might be many things, but HA is not one of them. =09 The disk subsystem is a single point of failure: you only have one = database. =09 --=20 Jared Still Certifiable Oracle DBA and Part Time Perl Evangelist =09 =09 --=20 Jared Still Certifiable Oracle DBA and Part Time Perl Evangelist -- //www.freelists.org/webpage/oracle-l