[CentOS] Control IO related to a process

Tue Sep 2 15:14:35 UTC 2008
William L. Maltby <CentOS4Bill at triad.rr.com>

On Tue, 2008-09-02 at 16:28 +0200, Lorenzo Quatrini wrote:
> Joseph L. Casale ha scritto:
> > Is there a way to nice the IO on a process such as dd?
> > If not, what could be a way to control the IO level of
> > such a process from bogging down a server to severely.
> > 
> As I was told few days ago you cold nice the whole process, eg.
> nice 19 if=/xxx of=/xxx bs=nnn
> This should give all the other process priority over dd

Saw the type fix. Just want to mention that the "bs=" can have a
substantial beneficial effect. By increasing the blocksize to a relative
large value, the number of system and I/O calls is reduced. This *may*
reduce the adverse effects that you see on overall system

I often use 8192, 16384 and even 8Mb, a "cylinder size".

Give it a try. YMMV.

> Hope this helps
> --
> Regards
> Lorenzo Quatrini
> <snip sig stuff>