Battery backup on the controller should help in this case. If there is none, "write back" mode should be used (instead of "write through"), loosing advantages of on-board caching (still helps with the "reads").
Igor Neyman, OCP DBA [EMAIL PROTECTED] ----- Original Message ----- To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]> Sent: Wednesday, April 10, 2002 6:58 PM > Much of the supposed 'speed' may come from onboard > caching on the controller. There is the minor risk > that a crash could come after Oracle commits the data > and before it is actually written to disk. > > --- [EMAIL PROTECTED] wrote: > > Hi all, > > > > We are running both a Hitachi 7700E and a 9960 disk > > subsystem here and we > > are getting ready to move our production DBs from > > the old(7700E) to the > > new(9960) Hitachi. We have had trouble in the > > past on the 7700E due to > > disk contention and layout, i.e. we weren't striped > > across the array groups > > very well.... this caused pretty poor I/O > > performance. This has been > > a learning experience for the DBAs and the SAs here > > for the logical vs. > > physical aspects of our disks. Anyway, to make > > a long story short, we > > are ordering disk for the move to the 9960 and we > > have 2 choices in disk > > sizes - 18GB and 73GB, and 2 choices in RAID - 1+0 > > and 5. I would like > > to get the smaller, faster 18GB drives in a RAID 1+0 > > configuration and > > stripe our data across the array groups as wide as > > possible. However, I > > am running into objections from the Hitachi people > > that their system is > > "soooo fast we need not worry about such minor > > details". I'm having a > > hard time believing that given our I/O problems on > > the 7700E. Performance > > is given a high priority here. > > > > What I would like to know is others' experience with > > disk subsystems - > > specifically Hitachi but EMC and others as well.... > > have you been able to > > "throw the disk in and forget it" or have you had > > success in getting to the > > dirty details? Have you tested or noticed an > > improvement with smaller, > > faster drives in a disk subsystem like the Hitachi > > or have you traveled > > that path and found no noticeable improvement? > > I'm looking for either > > a) ammunition that my view is correct, or b) I'm > > wrong and we can get > > bigger drives which will make Enterprise Planning > > very happy from a $$$ > > standpoint because our Hitachi capacity will last > > longer. > > > > We are running Oracle 8.1.7 / AIX 4.3.3 / Peoplesoft > > Financials version 8. > > 2 production databases , one 400 GB and the other > > about 1TB. We've got > > some other production DBs but these are our big > > guys. > > > > Thanks in advance for any and all input - any help > > is greatly appreciated. > > I'd be happy to share any info we have found up to > > this point and our > > experiences on the 7700E as well if anyone is > > interested - despite the fact > > I will probably bore you to death :-) > > > > John Dailey > > Oracle DBA > > ING Americas - Application Services > > Atlanta, GA > > > > > > > > -- > > Please see the official ORACLE-L FAQ: > > http://www.orafaq.com > > -- > > Author: > > 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). > > > ===== > Pete Barnett > Lead Database Administrator > The Regence Group > [EMAIL PROTECTED] > > __________________________________________________ > Do You Yahoo!? > Yahoo! Tax Center - online filing with TurboTax > http://taxes.yahoo.com/ > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.com > -- > Author: Peter Barnett > 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). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Igor Neyman 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).
