View Single Post

   
  #3 (permalink)  
Old 01-04-2008, 07:53 PM
Mark Taylor
 
Posts: n/a
Default Re: high outstanding I/O, finding responsible thread/process


that will get you the runnable thread ? if the thread is waiting for an
i/o to complete it will not be runnable..



The problem with the wait i/o figure as you quite rightly pointed out is
that single proc systems with 1 thread with an i/o outstanding and
nothing else runnable will show wait i/o as 100%.... its working as
designed...



Also note, that a kwrite or kread to an NFS mounted filesystem will not
show up on iostat as disk usage...



I did also come across an proxy app a while ago that was writing logs to
the proxy server over the network causing high wait i/o, but would not
show up on iostat or filemon.



The customer will have to live with that, or buy another system.



I would be tempted to install the latest nmon and run with the flags "c"
and "t" , then select "5" to give you the processes with i/o.



easier than mucking around in kdb or crash....



Rgds

Mark


--
Posted via http://dbforums.com
Reply With Quote