1

I'm using AIX 6.1 and for testing.
I want to clear the file system cache.
Something similar a this on linux : echo 2 > /proc/sys/vm/drop_caches

Is this possible?

ceinmart
  • 501
  • 1
  • 6
  • 17

2 Answers2

3

Failing an actual method to flush the cache you might be able to get away with tuning some VMM parameters to effectively flush your cache. 

vmo -L

Look at setting minperm% and maxperm% very low and strict_maxperm to 1. I don't have an AIX box handy to test what values it will let you set but I'm assuming 0 would fail, maybe: 

vmo -o minperm%=1 -o maxperm%=1 -o strict_maxperm=1 -o minclient%=1 -o maxclient%=1

Monitor with vmstat -v to see when/if it applies. You might need to do something memory intensive to trigger the page replacement daemon into action and take care of that 1%.

cat "somefile_sized_1%_of_memory" > /dev/null

Then reset them back to your normal values.

Matt
  • 8,841
  • 1
  • 26
  • 32
  • Perfectly and acceptable workaround! I just set the `maxclient%` to a value equal of minperm% and `strict_maxclient=1`, in less of 2 minutes 16GB of memory was freed. Now I will back the original values. Thanks! – ceinmart Jan 08 '14 at 17:18
1

The only thing I could find was this command :

mount -o rbrw

Link : https://www.ibm.com/developerworks/community/forums/html/topic?id=77777777-0000-0000-0000-000014315545#77777777-0000-0000-0000-000014315663

Other option will be unmonting the file-system wich will dump the cache.

Boogy
  • 876
  • 6
  • 8
  • Hy @Boogy, I already tested this before... not work for me because I need execute the command with users accessing the FS. This option need to umount first, which make it unfeasible. – ceinmart Jan 08 '14 at 15:04