On Wed, Nov 5, 2014 at 11:00 PM, Jimmy Lin <y2klyf+w...@gmail.com> wrote:
> Sorry I have late follow up question .... > > In the Cassandra.yaml file the concurrent_read section has the following > comment: > > What does it mean by " the operations to enqueue low enough in the stack > that the OS and drives can reorder them." ? how does it help making the > system healthy? > The operating system, disk controllers, and disks themselves can merge and reorder requests to optimize performance. Here's a relevant page with some details if you're interested in more http://www.makelinux.net/books/lkd2/ch13lev1sec5 > What really happen if we increase it to a too high value? (maybe affecting > other read or write operation as it eat up all disk IO resource?) > Yes -Bryan
