Falling back on my time as an AIX guru, I had set up striping in an RS/6000-F50 (yes, that ancient) acress three different sixpacks arranged to ensure that adjacent stripes were on a DIFFERENT SCSI controller.
Note that striping is *most* useful for an ADSM/TSM storage pool where most disk I/O is going to be sequential. Please note that I am *not* talking about a RAID5 array, which, if you want maximum performance, you want adjacent disks on a DIFFERENT bus-- SCSI, SATA, whatever-- in oder to minimize stalling of writes. (Sadly, this isn't particularly easy to do on PCI based systems even if you have a ServeRAID card.) Striping is best when data writes-- and reads-- are sequential and there are few competitors for the disk pool... and a DBMS using DMS might be a useful candidate. I am *not* convinced that this is an optimal solution for any other system since, with multple processes, while this does afford useful interleaving, it will still drive enough HDA motion to drive you crazy; I suspect that you would be better off with a set of small filesystems on small logical volumes that can be better kept in cache, but, then, your workload may preclude this. The hell of it is that, untill you kno what the workload looks like, you really can't choose a "final" disk layout strategy. "A good plan, executed today, will beat a perfect plan executed tomorrow." - Patton's Law In these days of SANs, howsomever, all bets are off since the actual disk setup is inside a black box full of compromises because the basic priority is to centralize disk storage and share resources... so, if you wanna measure disk performance when you're on a SAN, get some tea-leaves, since SANs impose a far more elastic ruler than using vmstat in a z/VM instance running Linux. -soup -- John R. Campbell Speaker to Machines souperb at gmail dot com MacOS X proved it was easier to make Unix user-friendly than to fix Windows ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
