Re: Informix Disk Mirroring

Ian MacGregor suggest in Informix-List-Id: <newsgate.204> using SQL*FORMS and user exits to achieve multi-machine database updates. I don't know Oracle but Informix doesn't appear to have quite the same facilities. But you could achieve something similar. Using Informix Net/Star to provide remote access to databases. All programs either written in C or 4GL would have to do two updates. First open one database, store original details, do the update, commit, close database. Second open other database, do the update, commit, close database if second database update failed open first database and using stored details rollback transaction manually. This would be very long winded, slow and developers would have to cope with all locking and transaction management themselves. I would think it would only really work where you were maintaining history type information on two different boxes. Alternatively I believe Informix are bringing out an AT&T Tuxedo Transaction Monitor version of Online, E-SQL and 4GL sometime in the next year. This using the facilities of Tuxedo should allow two phase commit across two databases operating on separate machines which should would solve the problem described above as well as provide higher transaction rates. Finally Informix-Star is supposed to get two phase commit sometime in the next year as well so you could use this. Both these solutions require you to adapt the application to produce the backup database rather than having it done automatically. Finally. Sorry Sequent. Yes Sequent also provide dual-porting the facility, as David Fuller says, has more to do with the drives than the box. I used Pyramid as an example as I happen to be more familiar with them. Cheers, -------------------------------------------------------------------- Name: Jim Gordon Internet: jgordon@ssf-sys.DHL.COM Company: DHL Systems Inc Phone: (415) 358-5911 Address: 1700 S. Amphlett Blvd. Fax: (415) 571-6429 San Mateo, CA 94402 --------------------------------------------------------------------