Solr hard commit

[Rallavagu]

All,

Are memory mapped files (mmap) flushed to disk during "hard commit"? If 
yes, should we disable OS level (Linux for example) memory mapped flush?

I am referring to following for mmap files for Lucene/Solr

http://blog.thetaphi.de/2012/07/use-lucenes-mmapdirectory-on-64bit.html

Linux level flush

http://www.cyberciti.biz/faq/linux-stop-flushing-of-mmaped-pages-to-disk/

Solr's hard and soft commit

https://lucidworks.com/blog/2013/08/23/understanding-transaction-logs-softcommit-and-commit-in-sorlcloud/

Thanks in advance.