[Xen-users] Disk IO

[Paras pradhan <pradhanparas@xxxxxxxxx>]

Hi,

I am doing disk IO test in dom0 and domU

dom0 has 1 CPU with 4GB of RAM and hardware raid 1

domU has 1 CPU with 1 GB of RAM. domU image is a filebacked image file in CLVM/GFS2 partition which connected to storage via 4mbps Fibre SAN.

I am using iozone to test the performance and here are the outputs

dom0:

"Record size = 4 Kbytes "

"Output is in Kbytes/sec"

"  Initial write "  282829.86 

"        Rewrite "  469707.22 

"           Read "  657510.62 

"        Re-read " 1293660.70 

"   Reverse Read "  837261.74 

"    Stride read "  861772.51 

"    Random read "  574933.67 

" Mixed workload "  486711.21 

"   Random write "  395390.98 

domU:

"Record size = 4 Kbytes "

"Output is in Kbytes/sec"

"  Initial write "  133933.96 

"        Rewrite "  394235.88 

"           Read "  710423.94 

"        Re-read "  508824.84 

"   Reverse Read "  407579.28 

"    Stride read "  401205.93 

"    Random read "  410340.80 

" Mixed workload "  338249.12 

"   Random write "  309791.69 

command used: /opt/iozone3_327/src/current/iozone -R -l 5 -u 5 -r 4k -s 100m -F /home/f1 /home/f2 /home/f3 /home/f4 /home/f5 | tee -a /tmp/ioz

one_results.txt &

As we can see above in domU, the drop is almost 50% (referring write and re write). Is this normal? Can it be tuned?.

Also any recommended tool to check IO ?

Thanks!

Paras.

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