Re: HP MC / Service Guard / Oracle 8i

Christian Reuß <christian.reuss_at_gmx.net> wrote:

>Hello,
>
>>
>> The second server is not involved until failure. We currently have three oracle
>> servers in an regular Serviceguard cluster. We have a group of instances running
>> as a "package" on each server. Two of the servers are production one is a test
>> server. The package has its own IP address and DNS entry. Your tnsnames.ora
>> points to the package name and the application uses that to connect to the
>> instance. During a failure serviceguard discovers that the oracle server is no
>> longer there. The backup server then activates the oracle vg's on the backup
>> server, brings up the oracle instances, and uses arp to point the IP address of
>> the package to the backup server. The applications will reconnect to the package
>> name which now points to the backup machine. The package name acts just like a
>> server name. You use tns to point to DBpackage rather than DBmachine.
>
>Usually the ip is the same on all servers. So its not transparent to the
>db users
>on which server the db is running in the first moment. The ip 'moves'
>together with
>the package?
>

Yes, the package IP address moves.

Each node (machine) in the service guard cluster has its own IP address, as does each no clustered system.

However each Service Guard package also has an IP address. During package start up the Volume groups belonging to the package are activated on the nod the package is starting on, the logical volumes are mounted and the packages IP address is added to the list of IP addresses for that nodes interface.

When the package is shutdown the reverse happens, Package IP address removed from the nodes interface, LVs unmounted and VGs deactivated.

So connecting to the package's IP address will connect you to which ever node the package has been started on.

Regards,

Ted.

| Ted Linnell                 <edlinnell_at_acslink.net.au>     |
|                                  |
| Nunawading, Victoria , Australia                           |
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