RE: RAC - Is it wise/ok/possible to run multiple databases across the same cluster?
- From: Job Miller <jobmiller@xxxxxxxxx>
- To: mwf@xxxxxxxx, post.ethan@xxxxxxxxx, "'Kerber, Andrew W.'" <Andrew.Kerber@xxxxxxx>
- Date: Tue, 1 May 2007 07:16:58 -0700 (PDT)
what are the demands that drive the requirement for multiple databases in the
same cluster vs. a single larger database using the resources of the cluster?
for those that have multiples in the same cluster, does each db have its own
shared home, are all the dbs on a particular node using the same local home, or
does each db on each node have its own local home?
I have heard cases where folks divide up nodes to form a set of smaller
clusters, where each cluster runs a separate db. In this scenario each box has
a single db on it (traditional best practice), and any box could be repurposed
to join any other cluster at any time it as needed. That assumes you have
enough boxes. If you are running 7 dbs in a 3 node cluster, it obviously
doesn't work.
Job
"Mark W. Farnham" <mwf@xxxxxxxx> wrote: v\:*
{behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:*
{behavior:url(#default#VML);} .shape {behavior:url(#default#VML);}
IF you?ve got the shared disks for all the databases ?zoned? for access by
all the hosts (machines) and sufficient interconnect bandwidth amongst the
machines, then it is really just a question of gracefully starting and stopping
the relevant instances of the databases on the various machines.
Automating all this to dynamically adapt to load spikes would be one of the
many conflicting definitions of ?grid.? Doing it ?by hand? at predefined
workshifts should be reasonably manageable. You *might* want to avoid actually
shutting down the non-prime-shift instances on C & D and just make it
impossible to open a session on them if memory is not an issue on the C & D
hosts. That depends on issues like pre-warming the cache, ?kept? lookup tables
and packages, etc. versus the resource cost of keeping the idle instances up
and checking them for blocks (which should approach zero cost as the length of
idleness increases).
Don?t confuse my statement that it should be possible with the idea that this
is the best architecture for a given system.
Regards,
mwf
---------------------------------
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Ethan Post
Sent: Monday, April 30, 2007 3:52 PM
To: Kerber, Andrew W.
Cc: oracle-l
Subject: Re: RAC - Is it wise/ok/possible to run multiple databases across the
same cluster?
OK, I had heard that perhaps there are issues because of the interconnect
uses UDP. The goal would is to for example allow say 3 databases access to
machines A & B during the day, while another database has exclusive access to C
& D, then at night allow one of the first three databases to access A, B, C &
D.
On 4/30/07, Kerber, Andrew W. <Andrew.Kerber@xxxxxxx> wrote:
None that are different than any other requirements. You don't even have
to cluster all the instances.
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto: oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Ethan Post
Sent: Monday, April 30, 2007 2:19 PM
To: oracle-l
Subject: RAC - Is it wise/ok/possible to run multiple databases across the same
cluster?
Are there any technical limitations in regards to running multiple databases
across the same set of servers in the same cluster
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