Database backups

> But how about the other performance bottleneck -- the single thread >I/O as done by tbtape to read data off the disk is still there. Large database backups are always going to be a headache. The use of incremental archiving reduces the time required but Informix only has a SINGLE process which scans all the chunks sequentially looking for "dirty" pages. If only a small part of the each table is "dirty", the tape drive will spend most of its time idle. Instead, the archiving software should really have a seperate process per chunk or table and each should write to the tape when required. This would mean that incremental backups will take less time. Let's hope v6 sorts this out. >I agree with you on DBEXPORT, but, if it's the only tool you have, you >make do with it. Some of us ain't lucky or rich enough for ON-LINE. The annoying feature of DBEXPORT is that it does an "update statistics" (6 hours on a 10GB database) before writing anything to tape. But once it starts writing, it is fast. I can't imagine why it needs to do that because doing a select count(*) on each table is virtually instant. David Chan "I hate computers but I keep going back because I refuse to allow a piece of refined rock beat me."