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 >
