Re: Informix vs. AIX Mirroring

} } In article <52iq0b$fgi@news.interlog.com>, John Morton } <mortonj@interlog.com> writes } >Hi there. We're just moving from a RAID5 box onto some SSA disk, so we } >have to think about mirroring. Informix recommends Informix mirroring, } >and IBM recommends AIX (what a shock!). We are running AIX 4.1.4 and } >Informix 7.20 on an 8-way RS6000. } > } >Seems to me that AIX mirroring on a JFS would be easier to manage than } >Informix mirroring and raw space, but I'm worried about performance } >.. it's a busy oltp application. } > } >Any ideas or opinions? } > } >John Morton } >mortonj@interlog.com } > } } The word from the tutor on my Informix Performance Tuning course last } summer said he has actually looked tried internally in Informix to find } out whether Informix mirroring is better than UNIX mirroring in terms } of performance. The answer was ' I can find nothing which indicates } anything either way'. Seems like Informix provided it so you could use } it If the operating system does not support mirroring. ALso another } tick on the list of features a 'good' database server provides and } relatively easy to implement. } } UNIX mirroring is normally done using a Logical Volume Manager. This } can also provide useful features such as making 2 disks look like one } big one. Making 1 big disk look like 2 disks etc. So it is more } flexible and you may as well let it do the mirroring as well. } } SO...use UNIX mirroring if available otherwise use Informix's } mirroring. I disagree. Filesystem damage can 'take down' a primary drive. Since it is generally a raw device - hte Unix mirroring will never notice a need to switch over where the Informix mirroring will. Where we have used Informix mirroring we have been very happy with it. Where we have not we have had this sort of problem. cheers j. _____________________________________________________________________________ Jack Parker - Hewlett Packard, DMD/IS Boise, Idaho, USA jparker@boi.hp.com Currently on loan to PLD/PE _____________________________________________________________________________ Outside of a dog a book is a man's best friend. Inside of a dog it's too dark to read. (Groucho Marx) _____________________________________________________________________________ Any opinions expressed herein are my own and not those of my employers. _____________________________________________________________________________