cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Bryan Talbot <bryan.tal...@playnext.com>
Subject Re: tuning concurrent_reads param
Date Fri, 07 Nov 2014 00:33:49 GMT
On Wed, Nov 5, 2014 at 11:00 PM, Jimmy Lin <y2klyf+work@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

Mime
View raw message