Recently I built a SAP IQ Multiplex cluster and ran into a self inflicted issue. After I configured the secondary nodes I updated the coordinator node (primary node) with the private (interconnect) and public (what you connect to with an application) connection information. Problem was, I made a small typo and didn’t catch it until after I tried starting the coordinator node.
I configured the coordinator node as such:
alter multiplex server ip_mpx_1 database '/dba/syb/iq_mpx.db' PRIVATE HOST 'node1-clu' PORT 5535 HOST 'myhost11' port 5535;
Upon attempting to start the coordinator node it failed to start with the following message:
MPX: startup failure message: server 'iq_mpx_1' was started on an incorrect host 'myhost1': this server was created with this connection string 'host=myhost11:5535 -- (stcxtlib/st_database.cxx 9455) Database server shutdown due to startup error
As soon as I saw the message I swore but the fix is quite simple. First, shutdown any secondary nodes. Update your IQ configuration file (or start command line options) so it starts in single node mode and overrides the multiplex configuration:
# single node mode -iqmpx_sn 1 #For use starting multiplex databases only. Starts the server with override to acknowledge that the write server is starting (1) on a different host, (2) with a different server name, or (3) using a different path to its catalog (.db) file. Do not start two write servers against the same database. -iqmpx_ov 1
Start the IQ coordinator and reissue the alter multiplex command:
alter multiplex server ip_mpx_1 database '/dba/syb/iq_mpx.db' PRIVATE HOST 'node1-clu' PORT 5535 HOST 'myhost1' port 5535;
Update your IQ configuration file to either remove or comment out the lines we added earlier.
Start up your coordinator. It should now start fine. Please note you will need to resync your secondary nodes before starting them.