[rrd-users] I/O Read overkill

[Fabien Wernli]

On Fri, Oct 26, 2007 at 09:47:38AM +0200, Fabien Wernli wrote:
> Before: 294% iowait
>         4.9MB/s read (hardware raid1 hidden to linux)
>         1.1MB/s write
>         4.6 loadavg
> 
> After:  318% iowait
>         57.9MB/s read (linux raid10 -> values have to be div by 2)
>         2.3MB/s write
>         8.9 loadavg
> 
> tests made with rrdtool 1.2.10 and 1.2.19.

I forgot to mention that old server was a 2.4 32bit kernel, new one being a
2.6 64bit.

also, I just tested rrdtool 1.3beta (w/mmap) and my problem seems to
disappear totally. I changed "use lib" in update script to use rrdtool 1.3b
at 12:25 (see graph).

http://swissunix.free.fr/rrd/rrd_perf_1.3beta.png

Now I don't understand why on earth it used to work so well on the old
server and rrdtool 1.2.10 ...