====== Benchmarking the cluster ======

===== IO Benchmarks =====

==== dd ====

==== iozone ====

Dowload on sourceforge, then build it using (need gcc and make) :

<code>
cd src; cd current
make linux-AMD64
</code>

The execute iozone using:
<code>
./iozone [options] /directory/to/write/to/for/bench
</code>

Now to use the tool, here are the options I used :
  * **-i** : test to use (if not specified, all of them). Tests are:
0=write/rewrite\\
1=read/re-read\\
2=random-read/write\\
3=Read-backwards\\
4=Re-write-record\\
5=stride-read\\
6=fwrite/re-fwrite\\
7=fread/Re-fread\\
8=random mix\\
9=pwrite/Re-pwrite\\
10=pread/Re-pread\\
11=pwritev/Re-pwritev\\
12=preadv/Re-preadv\\
  * **-r** : block size. I use **-r 8k**
  * **-s** : file size. I use **-s 20G** to avoid cache effects
  * **-t** : number of threads to use. Depend of your needs. Most of the time, the number of CPU cores, to simulate an MPI/OpenMP run writing
  * **-a** : do all the standard sizes/block combinations for this test, replace -s and -r
  * **-b** : provide the results in an xls file to plot graphs, **-b resultst.xls**

Example:

<code>
./iozone -i 0 -t 5 -r 8k -s 20G /scratch/testdir
</code>

Results looks like this:

<code>
	Children see throughput for  5 initial writers 	= 1345777.16 KB/sec
	Parent sees throughput for  5 initial writers 	= 1302776.63 KB/sec
	Min throughput per process 			=  264557.00 KB/sec 
	Max throughput per process 			=  273910.25 KB/sec
	Avg throughput per process 			=  269155.43 KB/sec
	Min xfer 					= 20255392.00 KB
</code>

External links :\\
http://socorro.readthedocs.org/en/latest/development/diskperformancetests.html\\
http://www.thegeekstuff.com/2011/05/iozone-examples/