Stiping cannot overcome PHYSICAL disk contention between redo logs, archived logs, database files, etc. 3 objectives: buffer I/O via cache; spread I/O via striping; and reduce contention via file segregation onto separate PHYSICAL devices. I want it all: cache, striping, and enough drives to PHYSICALLY separate contending files.
"I want to get PHYSICAL." - Olivia Newton John -----Original Message----- Sent: Tuesday, March 19, 2002 12:59 PM To: Multiple recipients of list ORACLE-L Doesn't "creative" striping solve this problem to some extent? -----Original Message----- Sent: Tuesday, March 19, 2002 12:24 PM To: Multiple recipients of list ORACLE-L This highlights problems with those larger drives... DBA's want more, smaller drives in order to spread I/O and reduce contention but SA's want fewer, larger drives in order to reduce expenses and ease administration. I once fought a major battle demanding smaller 4GB drives because the same amount of storage with the larger 9GB drives took away my ability to spread I/O and segregate contending files. After winning the battle they went ahead and bought the number of spindles I required but with the 9GB drives because the incremental cost was only another $100 per drive. So I got the number spindles I needed and a lot more storage capacity than was necessary but it was OK to "waste" space in order to gain performance. Large drives dedicated to redo logs can also be tempting for S/A's. They see all that extra space and figure it's a good place to put their monitoring utilities and system log files the look at you quizically when you explain that's why the database just slowed down. Then they walk away complaining how Oracle is so "wasteful" of disk space. Larger, fewer drives are NOT necessarily cheaper if you try to make up for I/O degredation by throwing CPU's and memory at the system. Storage may be cheaper on a $'s/GB basis but it still takes a lot to engineer optimum I/O throughput. Still wishing I has some 2GB SCSI drives... :-) Steve Orr -----Original Message----- Sent: Tuesday, March 19, 2002 8:13 AM To: Multiple recipients of list ORACLE-L Wouldn't it be cheaper just to replace each drive with a bigger one rather than buying all of the infrastructure related stuff? If you replace 8gb drives with 80gb drives you just saved 9 cabinets. -----Original Message----- Sent: Tuesday, March 19, 2002 9:08 AM To: Multiple recipients of list ORACLE-L I beg to differ. Each disk cost the disk price + 1/24 of the infrastructure costs. Yechiel Adar, Mehish Computer Services [EMAIL PROTECTED] > -----Original Message----- > From: Stahlke, Mark [SMTP:[EMAIL PROTECTED]] > Sent: Mon, March 18, 2002 10:33 PM > To: Multiple recipients of list ORACLE-L > Subject: RE: Disk is cheap? > > Robert G. Freeman - Oracle8i OCP wrote: > > > > But disk is cheap, right...? > > Or is that yet another Urban Legend??? > > Yes, that's another Urban Legend. > > Disk DRIVES are cheap, disk SPACE is not so cheap. > > Consider this example: I have a disk cabinet with 24 slots and 23 > disks. The 24th disk is cheap, but how much does the 25th disk cost? In > addition to the disk drive we need a cabinet, controllers, cache, host > adapters, cables, floor space, environmental controls, installation, > configuration, management, maintenance contract, and on and on. > > Mark Stahlke > Oracle DuhBA > Denver Newspaper Agency -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Orr, Steve INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
