>But we have big performance problems on an 40GB fs (LVM, >10 Stripes on >M9, 4 phys Escon) with an mySql-DB on it. Reorgs and even >selects >sometimes takes a lot of time. (Same on SCSI-Raid is >double-performance)
Two things: 1) A reorg does both a read and a write, so the activity of the 4 escon channels are at least double and a 40GB write is overwhelming the cache on a Shark (or almost any device), so you are running, probably, at back end speed for the shark. 2) people often fall into the trap of putting all their volumes in a single shark LSS because it is easy to administer - consecutive addresses and zipl dasd is just a range! However, this will reduce the performance of th backend to a single LSS. To get the best performance on a striped volume, each LSS must be in a different LSS or you may lose any advantage there is to striping. ===== Jim Sibley "Computers are useless.They can only give answers." Pablo Picasso (The NSHO's expressed here represents no-one but myself). __________________________________ Do you Yahoo!? New and Improved Yahoo! Mail - 100MB free storage! http://promotions.yahoo.com/new_mail ---------------------------------------------------------------------- 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
