Re: Data replication prerequisites

>Hi, >we are thinking of replicating our DB server to a second one for >migrating reasons. >The manuals say, the OS and the hardware of both server must be >identical. >To which detail is this true? We have one server, double PPro 200, 512 >MB, SCO 5.0.2, 28 GB HD, the second is Quad PPro 200, 1 GB, SCO 5.0.4, >36 GB HD with Raid 5. Our Informix is DS 7.20 >Will this work? It seems to me, that replicating should work on logical >basis, not on physical. > > Since you are on 7.2 you are using HDR, not CDR. HDR works by setting the second server in continual recovery mode and by shipping the logical logs from the primary to the secondary server. That means that the logs must be able to be replayed on the secondary system. We have to insure that things like byte swapping/ floating point data/calculation of dates, page size, etc. are handled the same on both platform. Hence the restrictions on physical similarity. The two machines that you have described fit this requirement. The fact that one is a double PPro and the other is a quad is not significant. Also, the difference in the disk layout is not significant as long as the secondary system has the same chunk names/sizes as the primary. The engine knows nothing about raid-5. If you want to do replication with a more "logical basis", you might want to check out CDR in the 7.22+ levels. Madison Pruet