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Home -> Community -> Mailing Lists -> Oracle-L -> [oracle-l] Re: Help With Veritas and my search for the Holy "I/O" Grail (testing with the tool from www.iozone.org)

[oracle-l] Re: Help With Veritas and my search for the Holy "I/O" Grail (testing with the tool from www.iozone.org)

From: <Brian_P_MacLean_at_eFunds.Com>
Date: Sat, 24 Jan 2004 22:58:30 -0700
Message-ID: <OFAA7B8B65.3F06E55E-ON07256E26.001F3C82-07256E26.0020D2BC@DeluxeData.Com>

Sorry, Mladen Gogala pointed out I forgot some version info

14798:oracle_at_roundtable> uname -a
SunOS roundtable 5.8 Generic_108528-27 sun4u sparc SUNW,Ultra-Enterprise 14798:oracle_at_roundtable> sqlplus -v
SQL*Plus: Release 9.2.0.4.0 - Production

                                                                                                                                    
                      Brian_P_MacLean_at_eF                                                                                            
                      unds.Com                  To:       oracle-l_at_freelists.org                                                    
                      Sent by:                  cc:                                                                                 
                      oracle-l-bounce_at_fr        Subject:  [oracle-l] Help With Veritas and my search for the Holy "I/O" Grail       
                      eelists.org                (testing with the tool from www.iozone.org)                                        
                                                                                                                                    
                                                                                                                                    
                      01/24/2004 05:29                                                                                              
                      PM                                                                                                            
                      Please respond to                                                                                             
                      oracle-l                                                                                                      
                                                                                                                                    
                                                                                                                                    




We have been trying to squeak out a little bit more bandwidth from our disk sub-system. I have been doing benchmarks using the tool from http://www.iozone.org. The command I use for the basic baseline test is
"iozone -Rab base.wks" which in effect takes all system default values to
do the reads/writes. I then test with the command "iozone -IRab vx_direct.wks" which now forces the reads/writes to direct I/O by issuing the command "ioctl(fd,VX_SETCACHE,VX_DIRECT);" in the .c program. When we compare the performance of the base to the direct timings it's like "WOW, Where have you been all my life".

So now we are puzzled as to just how in the 'el do we get Oracle to use the direct option. We have read the Veritas manuals and combed several pages on www.ixora.com.au (Steve Adam's site). The mount options/combinations we have tried are "mincache=direct,convosync=direct" and
"convosync=direct,mincache=dsync". The base line testing with iozone is
between 50 and 100 percent slower with either of these mount options in place. Running iozone with the "-I" (vx_direct enabled) continues to scream regardless of what we do to the mount points.

So now, WTF do I do.

PS: The first person who suggests raw disk or QIO has to find me a shrubbery) Received on Sat Jan 24 2004 - 23:58:30 CST

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