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
allenj wrote: > > 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 I have to disagree with the Murray. It is best, IMHO, to retain control over individual spindles. OS mirroring is fine, but occasionally you can run into problems where the disk is fine according to the OS, but there is some informix problem with it. In which case your OS mirroring isn't buying you anything. On the other hand I've only seen such a mirroring scheme be of use once. You will probably get better performance out of OS mirroring. cheers j. (aka jparker@epsilon.com)