Informix replication doesn't....
Posted in 1994
I heard the following about Informix's replication capabilities in the v6.+ and was wondering if I could get any confirmation either way from the net. (1) The primary and secondary site hardware must be the same, or atleast offer identical paging structure. (2) The OnLine config. on both the primary and secondary sites must be set up exactly the same. (3) You can only have one secondary site per primary site, i.e. a 1:1 correspondence between primary and secondary sites. (4) Secondary sites are read-only. (5) From the secondary site, you can not determine if a failure is at the primary site itself or a failure of the network. (6) Launching the entire replication process is difficult because both sites have to be kept closely in sync. (7) There are no administrative tools, just a few variables that can be queried or set to direct some of the replicate process behavior. (8) There is no mechanism for resolving inflight transactions that do not make it to the replicate site in the case of a hot-site backup scenario. Re- syncing the primary site after it comes back on-line is not possible without heavy manual intervention. (9) High transaction rates on the primary replication site can cause the log to grow to fast for replicates to keep up....the result is loss of data from the logs. I know that everybody else's replication approach suffers from some if not all of these problems, but most of these I heard at LAST YEARS Informix User Conference (couldn't afford to go this year) from the Informix product manager. I was just wondering if things had changed and if anyone in the know could shed some light on these issues. Bill Duncan