On Oct 19, 2010, at 7:34 PM, Aleksey Tsalolikhin atsaloli.tech@gmail.com wrote:
Still seeing the glitch every 5-20 secs after remounting with "commit=6000".
On Tue, Oct 19, 2010 at 4:00 PM, Ross Walker rswwalker@gmail.com wrote:
You could also reduce the dirty interval in sysctl so it flushes sooner therefore flushes less data each time.
OK. It's worth a shot. Any idea what the default value is? I'm not sure what value to put in here. I know I want to reduce it but I don't want to break my friend's system either.
http://www.mjmwired.net/kernel/Documentation/sysctl/vm.txt
109 dirty_expire_centisecs 110 111 This tunable is used to define when dirty data is old enough to be eligible 112 for writeout by the pdflush daemons. It is expressed in 100'ths of a second. 113 Data which has been dirty in-memory for longer than this interval will be 114 written out next time a pdflush daemon wakes up.
There are several dirty tunables, try a 'sysctl -a | grep dirty'
Try limiting both the amount if dirty memory to hold and the number of seconds to hold it. Defaults are way too liberal and if you are processing a lot of data can both expose you to extreme data loss in a system failure and bottle neck your storage during pdflush.
-Ross