>> RAC is one database with multiple nodes >> if you have two disk arrays, >> how can it be one database?=20 It can't...I mean I guess HP would argue that this is the same "logical database",=20 but I'm sure that there are *two* "/../system.dbf" datafiles at "two" different data centers!? and that is not one "physical database"... Chris Marquez Oracle DBA HEYMONitor(tm) - heymonitor.com "Oracle Monitoring & Alerting Solution" -----Original Message----- From: Paul Baumgartel [mailto:paul.baumgartel@xxxxxxxxx]=20 Sent: Wednesday, January 26, 2005 4:24 PM To: Marquez, Chris Cc: oracle-l@xxxxxxxxxxxxx Subject: Re: intel clusters in a box Chris, Yes, I am also skeptical of Extended Cluster for RAC, and the thing that trips me up is the software replication. If it's true RAC, it's one database with multiple nodes; if you have two disk arrays, with replication (mirroring) between two arrays involved, how can it be one database? I just don't see how that works. PB On Wed, 26 Jan 2005 13:11:31 -0500, Marquez, Chris <CMarquez@xxxxxxxx> wrote: >=20 > Paul, >=20 > Sorry for the slow reply. >=20 > >> http://h71028.www7.hp.com/enterprise/cache/10084-0-0-225-121.aspx > >> The Extended Cluster for RAC is... > >> a virtualized application environment > Not sure what this means. >=20 > >> a replicated and synchronized database. > "replicated"...This simply scares me... :O| >=20 > >>Extended Cluster for RAC works in an active-active mode > Would have to see it action before buying in. >=20 > >>across two datacenters, up to 100 kms apart > 100 kms =3D 62 miles...nice but as I said before this (SAN syncing) = has=20 > geographic limitations. My clients have data centers in different US=20 > states if the have one at all). >=20 > >>HP worked closely with Oracle, AT&T and Nortel Networks > Yeah...got to have a great network to before even talking. >=20 > >> http://h71028.www7.hp.com/enterprise/downloads/SgeRAC_wp_030504.pdf > There is a nice graphic on page 4 of the .pdf >=20 > Also on page 5; > >> "Database replication is achieved via host--based software=20 > >> mirroring, with RAC synchronizing the database caches via Cache=20 > >> Fusion." >=20 > BUT what happens when these to "physical differ database (being > replicated) become out of sync!? > Sorry but I'm no fan of "software based replication"...this is counter > the concept of OPS/RAC...which his based on hardware=20 > replication/redundancy/sharing! >=20 > If you have sat and watched your (v$...) sessions waiting for "global=20 > cache..." with two RAC nodes side by side, I can only imagine the fun=20 > it would be with two RAC nodes in different data centers. >=20 > This all sounds good, but simply, "why"? > Nice to see, but honestly I would never want to mange this...I'll take > DataGuard for now. >=20 > I don't want to sound cynical...this is very cool and good info...I=20 > appreciate it. Oracle OPS has come a long way. >=20 > Chris Marquez > Oracle DBA > HEYMONitor(tm) - heymonitor.com > "Oracle Monitoring & Alerting Solution" -- //www.freelists.org/webpage/oracle-l