Informix

A word of warning for a lesson learned the hard way.

When setting up groups in sqlhosts, you need to define a group ID. There's a poorly-documented (or perhaps undocumented) requirement that the Group ID used in the i= parameter must be a number between 1 and 32767. I don't recall this being a problem in 12.10, but I definitely ran into situations (involving the Connection Manager) where it's caused problems in 14.10 / CSDK4.50. But even through 14.10.xC5, it would let you get away with a group ID larger than 32767 in most circumstances.

Not anymore.

As of 14.10.xC6, if it finds a ER group with an ID > 32767, ER will fail to start. It will log a single-line error in the online.log that's easy to miss.

Worse, when this situation occurs, you'll get a loop of ER's infamously unhelpful error messages.

To wit:

$ onstat -

IBM Informix Dynamic Server Version 14.10.FC6 -- On-Line -- Up 16:58:14 -- 2422784 Kbytes
2021-06-24 14:48:18

$ cdr list server
command failed -- Enterprise Replication not active (62)
$ cdr start
command failed -- Enterprise Replication already active (63)
$ cdr stop
command failed -- Enterprise Replication not active (62)

This one took me a while to figure out, so I figured I'd save you the trouble?

[ Why have group IDs that are > 32767? Because in our case, we had the group ID tied to the associated port number for simplicity. Can't do that any more.... ]