Unix has a “buffer cache”, often called a file cache. This chapter discusses the Linux buffer cache, which is very similar to other Unix implementations. Essentially, all unused RAM is used to make disk access faster.
http://www.tldp.org/LDP/sag/html/buffer-cache.html <http://www.tldp.org/LDP/sag/html/buffer-cache.html> wunder Walter Underwood wun...@wunderwood.org http://observer.wunderwood.org/ (my blog) > On Oct 7, 2015, at 3:40 AM, Toke Eskildsen <t...@statsbiblioteket.dk> wrote: > > On Wed, 2015-10-07 at 07:03 -0300, Eric Torti wrote: >> I'm sorry to diverge this thread a little bit. But could please point me to >> resources that explain deeply how this process of OS using the non-java >> memory to cache index data? > > http://blog.thetaphi.de/2012/07/use-lucenes-mmapdirectory-on-64bit.html > > Shawn Heisey: >>> Whatever RAM is left over after you give 12GB to Java for Solr will be >>> used automatically by the operating system to cache index data on the >>> disk. Solr is completely reliant on that caching for good performance. >> >> I'm puzzled as to why the physical memory of solr's host machine is always >> used up and I think some resources on that would help me understand it. > > It is not used up as such: Add "Disk cache" and "Free space" (or > whatever your monitoring tool calls them) and you will have the amount > of memory available for new processes. If you start a new and > memory-hungry process, it will take the memory from the free pool first, > then from the disk cache. > > > - Toke Eskildsen, State and University Library, Denmark > >
