Hi, As per the post "The Generics Policeman Blog <http://blog.thetaphi.de/2012/07/use-lucenes-mmapdirectory-on-64bit.html>" , I am using the MMapDirectory for faster access(search and update operations ,mainly search) of Lucene 4.8.1 index files. I am contemplating what is the optimal maximum MMap value for my indexes. Is default i.e. 1 GB (1 << 30) or higher?
I have 6 indexes of size varying from 65GB to 6 GB. Currently, I am using 1 GB as maxChunkSize : - *MMapDirectory(file, null, 1<<30) *for all indexes. But thinking of specifying the higher value for mmap (1 GB or higher) for bigger index having 65GB size and lower value (0.5 GB or less) for smaller index having size of 6 GB. Any suggestion/guidance on it ? Also, per blog mmap is not a size of physical memory allocation but just a address space to map the index files. How to allocate more RAM to index files for better performance? We have enough RAM free out of 64 GB. Per blog, one should use the mmap file, like - *MMapDirectory(file, null, 1<<30) *and let OS manage the physical memory allocation for the index files. Is my understanding correct ? The Generics Policeman Blog <http://blog.thetaphi.de/2012/07/use-lucenes-mmapdirectory-on-64bit.html> :- - *MMapDirectory does not consume additional memory and the size of mapped index files is not limited by the physical memory available on your server.* By mmap() files, we only reserve address space not memory! Remember, address space on 64bit platforms is for free! Thanks Gaurav
