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

From: Brian_P_MacLean@xxxxxxxxxx
To: oracle-l@xxxxxxxxxxxxx
Date: Sat, 24 Jan 2004 22:58:30 -0700


Sorry, Mladen Gogala pointed out I forgot some version info

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






                                                                                
                                                    
                      Brian_P_MacLean@eF                                        
                                                    
                      unds.Com                  To:       
oracle-l@xxxxxxxxxxxxx                                                    
                      Sent by:                  cc:                             
                                                    
                      oracle-l-bounce@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)

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

Other related posts: