Re: Disk Layout recommendation

Jonathan Leffler wrote: > You don't mention which version of IDS you are using (nor which > platform), but I assume it is not 9.40. If it were, then I'd > recommend using large chunks for dbs0 (the main dbspace). Sorry. Thought of that after I already hit send. Anyway, it's 7.31.UC4 on HPUX 11.0 (using KAIO). > Ideally, you want the root dbspace and the logs on separate (and > mirrored) disks - and for maximum performance, you want both of those > separate from the main data dbspace. One of the disadvantages of the > new big disks is that it is harder to achieve that separation. In > your circumstances, I'd probably put the logs and the root dbspace on > one pair of disks (and I might not even have a separate log dbspace > given that it is all on the same spindle), and I'd place the other > dbspaces on the other four disks. Yes, by all means increase the size > of the chunks. ... use 2 GB chunks rather than smaller ones. > You said dbs0.x spaces are striped across a pair of disks? So you > have a logical volume manager at work? That complicates the issue in > some respects, or it makes your work at the Informix level less > relevant. You can either rely on the LVM to balance the load, or you > can use Informix to balance the load, but having both at work is > likely to be counter-productive. ... My view, not substantiated by > recent experience, is that you should use the lowest available level > of mirroring, provided that you monitor it for error reports. If the > hardware provides mirroring, use that; else if the o/s or LVM provides > mirroring, use that; only if nothing else does mirroring should you > use the Informix mirroring. ... > Even with KAIO and the like, there should be no way for Informix > mirroring to outperform the o/s or hardware level mirroring. Unfortunately, the hardware is JBOD and we haven't purchased the HP Mirror-UX option so neither HW or OS mirroring is an option. Tight budget, informix has mirroring so why do we need it elsewhere! :( Thanks for your recommendations Jonathan. I had been thinking along roughly those lines although I had thought to leave the dbspaces striped. I've learned a lot from this group, especially you and Art. Thanks to everyone here. -- David Kleppinger - SysAdmin/DBA

"zdavek" <zdavek@hotmail.com> wrote in message news:640ad61c.0305280547.467c0f42@posting.google.com... > Unfortunately, the hardware is JBOD and we haven't purchased the HP > Mirror-UX option so neither HW or OS mirroring is an option. Tight > budget, informix has mirroring so why do we need it elsewhere! :( Because HP-UX (or hardware) mirroring has more uses, is more versatile, and is just better.