Cluster with Informix Database

[Schnabel]

Hi

I'm very new to service guard clusters. Can anyone tell me something about running an Informix database on a Service Guard Cluster?
Can both nodes access the database at the same time?
Do I have to install a database server on each node? (importent for licensing )
How do clients access the database.

[Rainer von Bongartz]

Hi,

if you don't have extended Parallel Server (XPS) from Informix only on machine can connect to the DB.
You can install INFORMIX on a shared volume group
and switch it to the other machine via service guard
along with your database.
You cannot do this if you have more than one INFORMIX instance on one Server and you want to switch only one instance.
This would mean that you try to switch INFORMIX installation directory which is in use by the other instance.
Clients access the DB with $INFORMIXDIR, $INFORMIXSERVER and the IP-address of your Service Guard package.

Clients access the database with $INFORMIXSERVER

[Schnabel]

Thanks. That helped.
Only one more simple question.
Running a informix db on a "2-nodes-cluster" what exactly happens if the node on witch the database is running fails?
Does the client lose the connection?

[Rainer von Bongartz]

short answer: yes

[James R. Ferguson · Accepted solution]

Hi:

For a good, general overview of MC/ServiceGuard, see "Managing MC/ServiceGuard (HP-UX 11.0, HP-UX 11i)":

http://docs.hp.com/hpux/onlinedocs/B3936-90026/B3936-90026.html

...JRF...

[Schnabel]

Thats bad.
I thought with MC Service Guard the application switches automaticly to the second node and the clients are not affected.

[Rainer von Bongartz]

depending on your configuration in $ONCONFIG
you can drop the 'down time' of INFORMIX in case of
a MC/SG Switch to a few seconds.

[Schnabel]

seconds?

But i have to restart the db-server then, or not?
And all clients have to login again then.

[Tim D Fulford]

HI

From the above I take it that the salesman did a very good job! All is not quite as bad as it seems though.

o If you have spare LANS cards and you have a lan card failure SG will (when configured correctly) automatically fail the IP address(es) over seemlesly. This means no logging in etc.

o Most DB's are accessed by applications. If you put this application on a different server than your DB server and you code is written such that you do a conect - do something - disconnect, again this suits SG, minimal outages. This obviously is only appropriate for OLTP type of queries

o You can have just one version of informix software BUT some people (well everywhere I have worked) prefer two as you can do upgrades on the standby node, failover & repeate on remaining node, reducing outage times. The choice is yours!! [if you do use just one installation remember to put the soft links required in /usr/lib/[iosm??a.sl ipldd??a.sl] to $INFORMIXDIR/lib/. !!]

Good luck

Tim