On Mon, Mar 30, 2015 at 3:58 PM, Dave Johansen <davejohansen@gmail.com> wrote:
> I noticed on RHEL 6 that when a large amount of disk I/O is happening that
> CPU bound tasks "slow down". I have been able to reproduce it in Fedora 21
> as well and here are the instructions of how I can reproduce it with a
> simple test:
Writing to disk is not "free". There is overhead in writing the data,
especially if the files are being re-arranged and the directory
structure revised, and there's overhead in doing it safely to avoid
accidental loss of data.
There are options to improve such performance, such as using the
'noatime' option, or using well optimized filesystems. But there are
certainly limits.