Tuesday, March 20, 2012

Cluster active/active/active

Dear, I am needing to grant tolerance to shortcomings to a Server
SQL. The consultation is the following one, in Windows 2003 can have up to 8
nodes
in a Cluster, in my Cluster at the moment have two instances of SQL, it is
to say, an active/active, according to the above-mentioned, I can add him a
third
node to the Cluster, but I don't have clear if I can install a third
instance
in that same cluster, a thing like activo/activo/activo, somebody has him
fact or is it theoretically and technically fctible...?, according to my
theory,
it could be feasible, since to the moment to install the third instance
Virtual, he/she should only choose available two nodes of the three....,
now
not you if this is feasible in he/she practices it.
Thank you for their attention.
Greetings.
Atte.,
Carlo Sorrel
Hi
Windows 2003 supports 8 node clusters.
SQL Server 2000 supports 4 node clusters, with up to 16 instances of SQL
Server per cluster.
Yes, adding a 3rd node, and running a 3rd instance is possible as is being
used by various customers of Microsoft.
Done think about active/passive active/active etc, think using the new
terminology of "instances".
The biggest thing you have to worry about in multiple instance clusters is
if all instances were to be failed over to 1 node, does the 1 node have
enough RAM to support them all? If you have 3 nodes, each node with 4 GB RAM
and you allocate 2GB per instance, and you failed all 3 instances over to 1
node, the 1 node would not be able to start the last instance as there is
2GB RAM too little.
If you had 2 nodes, in effect, you could run 8 instances on node 1 and 8
instances on node 2, or any combination, adding up to 16, assuming you have
enough resources.
Regards
Mike Epprecht, Microsoft SQL Server MVP
Zurich, Switzerland
IM: mike@.epprecht.net
MVP Program: http://www.microsoft.com/mvp
Blog: http://www.msmvps.com/epprecht/
"Carlo Sorrel" <csorrel@.hotmail.com> wrote in message
news:uYaN9BhbFHA.1040@.TK2MSFTNGP10.phx.gbl...
> Dear, I am needing to grant tolerance to shortcomings to a Server
> SQL. The consultation is the following one, in Windows 2003 can have up to
> 8 nodes
> in a Cluster, in my Cluster at the moment have two instances of SQL, it is
> to say, an active/active, according to the above-mentioned, I can add him
> a third
> node to the Cluster, but I don't have clear if I can install a third
> instance
> in that same cluster, a thing like activo/activo/activo, somebody has him
> fact or is it theoretically and technically fctible...?, according to
> my theory,
> it could be feasible, since to the moment to install the third instance
> Virtual, he/she should only choose available two nodes of the three....,
> now
> not you if this is feasible in he/she practices it.
> Thank you for their attention.
> Greetings.
> Atte.,
> Carlo Sorrel
>

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