Swappiness is actually a fairly weak hint to linux: http://www.linuxvox.com/2009/10/what-is-the-linux-kernel-parameter-vm-swappiness
On Sat, Apr 14, 2012 at 1:39 PM, aaron morton <aa...@thelastpickle.com> wrote: > From https://help.ubuntu.com/community/SwapFaq > " > swappiness=0 tells the kernel to avoid swapping processes out of physical > memory for as long as possible > " > > If you have swap enabled at some point the OS may swap out pages, even if > swappiness is 0 and you have free memory. Disable swap entirely if you want > to avoid this. > > > Cheers > > ----------------- > Aaron Morton > Freelance Developer > @aaronmorton > http://www.thelastpickle.com > > On 15/04/2012, at 1:37 AM, R. Verlangen wrote: > > Maybe it has got something to do with "swapiness", it's something you can > configure, more info here: > https://www.linux.com/news/software/applications/8208-all-about-linux-swap-space > > 2012/4/14 ruslan usifov <ruslan.usi...@gmail.com> >> >> I know:-) but this is not answer:-(. I found that on other nodes there >> still about 3GB (on node with JAVA_HEAP=6GB free memory also 3GB) of free >> memory but there JAVA_HEAP=5G, so this looks like some sysctl >> (/proc/sys/vm???) ratio (about 10%(3 / 24 * 100)), i don't known which, >> anybody can explain this situation???? >> >> 2012/4/14 R. Verlangen <ro...@us2.nl> >> >>> Its recommended to disable swap entirely when you run Cassandra on a >>> server. >>> >>> >>> 2012/4/14 ruslan usifov <ruslan.usi...@gmail.com> >>>> >>>> I forgot to say that system have 24GB of phis memory >>>> >>>> >>>> 2012/4/14 ruslan usifov <ruslan.usi...@gmail.com> >>>>> >>>>> Hello >>>>> >>>>> We have 6 node cluster (cassandra 0.8.10). On one node i increase java >>>>> heap size to 6GB, and now at this node begin grows swap, but system have >>>>> about 3GB of free memory: >>>>> >>>>> >>>>> root@6wd003:~# free >>>>> total used free shared buffers >>>>> cached >>>>> Mem: 24733664 21702812 3030852 0 6792 >>>>> 13794724 >>>>> -/+ buffers/cache: 7901296 16832368 >>>>> Swap: 1998840 2352 1996488 >>>>> >>>>> >>>>> And swap space slowly grows, but i misunderstand why? >>>>> >>>>> >>>>> PS: We have JNA mlock, and set vm.swappiness = 0 >>>>> PS: OS ubuntu 10.0.4(2.6.32-40-generic) >>>>> >>>>> >>>> >>> >>> >>> >>> -- >>> With kind regards, >>> >>> Robin Verlangen >>> www.robinverlangen.nl >>> >> > > > > -- > With kind regards, > > Robin Verlangen > www.robinverlangen.nl > > -- Jonathan Ellis Project Chair, Apache Cassandra co-founder of DataStax, the source for professional Cassandra support http://www.datastax.com
