Re: Informix data fragmentation or RAID disk

!In article <jlumbleyDIKJoz.Fsx@netcom.com>, jlumbley@netcom.com says... !> !>Database Storage Solutions (76043.1656@CompuServe.COM) wrote: !>: RAID striping (with and without parity) creates large logical !volumes !>: which can be partitioned into multiple units. RAID disks can get !>: fragmented like other disks. How it impacts your application depends !>: alot on read/write ratios, random vs. sequential nature, etc. -- !>: so go ahead and ask your RAID vendor to analyze your particular !>: computing environment for the most realistic prediction. !>: Robert @ MTI !> !>This may not be such a good idea. Unless your RAID vendor is **very** !>knowledgeable about 7.xx Informix, take the advice with a grain of !salt. !>Ask to see one of their systems running a 7.xx database. !> !>If you are concerned with performance, stay away from RAID...7.XX !allows !>you to fragment the tables over separate disks and does such things as !>parallel queries using multiple threads to take advantage of the fact !>that the database knows exactly which disk to search for a particular !row. !>If you use RAID, you are letting the hardware make the decisions, and !the !>RAID hardware/software knows much less about your database than 7.XX !does. !> !>If you are not pushing the database that hard, you may very well find !out !>that the increased security of RAID more than makes up for the !performance !>hickey. !> !>Joe Hi I find this subject very interesting. I have heard this before and it raised a few questions re raid/non raid with high-end database systems. From my point of view i thought perhaps wrongly that all the raid would do assuming it was used to stripe (raid 0) was increase the number of spindles thereby enhancing the database engines access to the data for larger data blocks. I would like to hear from anyone who understands the theory of this. Thanks John