Thanks for link. But for me still present question about free memory. In out cluster we have 200 IOPS in peaks, but still have about 3GB of free memory on each server (cluster have 6 nodes tho there are 3*6=18 GB of unused memry). I think that OS must fill all memory with pagecache (we do backups throw DirectIO) of SStables, but it doesn't do that and i doesn't understand why. I can't find any sysctl that can tune pagecache thresholds or ratio.
Any suggestion???? 2012/4/18 Jonathan Ellis <jbel...@gmail.com> > what-is-the-linux-kernel-parameter-vm-swappiness<http://www.linuxvox.com/2009/10/what-is-the-linux-kernel-parameter-vm-swappiness>
