Re: Creating dbspaces in HP-UX LVM disks

On Tue, 30 Jan 1996, Craig Ostrom wrote: > We have a HP T500 which uses HP's logical volumes to organise the disk > space. We want to create dbspaces on seperate devices to speed up our > databases. What do we do to either switch off the HP stuff or use the > logical volumes as they are. > You may want to use logical volumes, but perhaps not as they are layed out right now. What you asked implies (at least to me) that the volumes each cover pieces or all of multiple physical drives. You're correct to avoid that. What you want for Informix is lots (the number is up to you) of volumes, each no larger than 2 GB and each on only one drive. If you have drives of > 2 GB (4, 9,a nd 10 GB are common), then divide the physical drives into multiple logical volumes. You will then have multiple chunks sharing a physical drive, so be careful about how you assign tables to dbspaces (which are composed of chunks.) What's essential is that there be no filesystem on the volumes, or at least no files in such filesystems, and to use the charater special device as the chunk pathname. That provides the most streamlined access through the OS, bypassing the filesystems and their buffer cache. If you can get away with no logical volumes, then do so. That's an even more streamlined path through the OS to the device. Dick Snoke dsnoke@informix.com Informix Software (404)-395-2308 Advanced Technology Group Atlanta, Georgia