RE: 7.31 disk layout/striping questions

Stripe over all the disks. Place the tables that are heavily used in chunks probably near the center of the disks (to keep the heads there). [I have never been keen to place tables and indexes manually in order to even the reads between different disks]. Use OS mirroring. I believe that Informix reads the first half of a chunk from the primary and the second half from the mirror, whereas the OS should share the read load evenly. Murray Wood -----Original Message----- From: allenj [SMTP:allenj@ndr.com] Sent: Friday, May 21, 1999 6:42 AM To: informix-list@iiug.org Subject: 7.31 disk layout/striping questions As part of my 7.22 -> 7.31 upgrade, I am redoing the disk layout. A few questions for the gurus: Environment: HP-UX 10.20 HP quad processor K260 1 gig RAM 20 gig database 3 or 4 mirrored singleton disk drives I will be using HP-UX LVM to create 2 gig logical volumes on the drives (which are all larger than 2 gigs). I will then create my chunks in these volumes. Most of the chunks will be 2 gigs, but if smaller (ala detached indexes or single table dbspaces), the offsets will work. Question: Is it better to create lvm volumes striped across the disks and then just point the informix chunks one after another at those volumes? (The OS is striping) OR Is it better to create lvm volumes on single disks (no lvm striping), then create the informix chunks one after another across the disks/volumes? (Informix is striping). I am leaning towards Informix mirroring rather than the HP-UX/Mirror. I will probably utilize some expression-based fragmentation. Any opinions? Allen Jantzen, DBA Ned Davis Research