I am sorry but you said: *you need enough free RAM for the OS to cache the maximum amount of disk space all your indexes will ever use*
I have made an assumption my indexes at my machine. Let's assume that it is 5 GB. So it is better to have at least 5 GB RAM? OK, Solr will use RAM up to how much I define it as a Java processes. When we think about the indexes at storage and caching them at RAM by OS, is that what you talk about: having more than 5 GB - or - 10 GB RAM for my machine? 2013/4/10 Shawn Heisey <s...@elyograg.org> > On 4/9/2013 7:03 PM, Furkan KAMACI wrote: > > These are really good metrics for me: > > > > You say that RAM size should be at least index size, and it is better to > > have a RAM size twice the index size (because of worst case scenario). > > > > On the other hand let's assume that I have a RAM size that is bigger than > > twice of indexes at machine. Can Solr use that extra RAM or is it a > > approximately maximum limit (to have twice size of indexes at machine)? > > What we have been discussing is the OS cache, which is memory that is > not used by programs. The OS uses that memory to make everything run > faster. The OS will instantly give that memory up if a program requests > it. > > Solr is a java program, and java uses memory a little differently, so > Solr most likely will NOT use more memory when it is available. > > In a "normal" directly executable program, memory can be allocated at > any time, and given back to the system at any time. > > With Java, you tell it the maximum amount of memory the program is ever > allowed to use. Because of how memory is used inside Java, most > long-running Java programs (like Solr) will allocate up to the > configured maximum even if they don't really need that much memory. > Most Java virtual machines will never give the memory back to the system > even if it is not required. > > Thanks, > Shawn > >
