When setting up your clustering design , what would be the
main reasons for adding new instances to the pre-existing
ones? Basically I need a list of reasons of why add new
instances, thanks.

One instance could be for high-sensitivity data for which the DBA's should
have a security clearance whereas the other instance is for general purpose
data. You need high availability for both but only the super DBA's could be
allowed into both while the regular DBA's are in just the general one.

Also, if you have conflicts arising from multiple definitions for entries in
sysmessages for the same message ID and language ID, then you can have a
separate instance for each.

--
Tom

---------------------------------------------------------------
Thomas A. Moreau, BSc, PhD, MCSE, MCDBA
SQL Server MVP
Columnist, SQL Server Professional
Toronto, ON Canada
www.pinnaclepublishing.com/sql


"Steve" <anonymous (AT) discussions (DOT) microsoft.com> wrote

When setting up your clustering design , what would be the
main reasons for adding new instances to the pre-existing
ones? Basically I need a list of reasons of why add new
instances, thanks.

I find that if you have data that is logically unrelated, multiple instances
can give soem scale-out capability. I have a 4-node, 3 instance cluster
where each instance holds data that is never checked or compared directly
against data in another instance.

--
Geoff N. Hiten
Microsoft SQL Server MVP
Senior Database Administrator
Careerbuilder.com


"Steve" <anonymous (AT) discussions (DOT) microsoft.com> wrote

Another reason is to make it easier to heandle conflicting
collations among different databases.

Linchi