Linux != PC as Linux on Power = 8 times faster or is it?
nagger 100000MRSJ Comments (2) Visits (7474)
I have been installing beta copies of PowerVC, the new IBM product which is available tomorrow 6th Dec 2013. It is quick to install and allows rapid rolling out of new virtual machines to a group of physical Power machines from your list of pre-packaged software images in just a few seconds of your time and roughly 2 to 3 minutes elapse time till you can login and use it. PowerVC is based on OpenStack which has lots of modules to install and configure. It is installed on Red Hat Enterprise Linux RHEL 6.4 on Power or x86 - So it is a level playing field for the OS.
PowerVC install time on Power is 17 minutes - "Cool!"
PowerVC install time on x86 Laptop is 133 minutes - "Good grief! I was there till 8 pm waiting for it to finish!"
Well, I was not expecting that large a difference!
So there you have it the final proof that Power is roughly 8 times faster than Intel.
But ... watching the install with the best performance monitoring tool on the planet (that would be nmon for Linux, of course), the install process is 99% of the time waiting for the disks. So there is a bottleneck with the disk running at 95% to 100% performing random write I/O with small blocks while it is creating databases. OpenStack's various modules have five databases to create and fill up with data during the install. The internal Laptop disk has to actually perform all the disk writes synchronously and its not a particularly fast disk. The V7000 has a large write cache so it returns immediately and does the writing in the background later to 24 actual disks.