Friday, July 31, 2009

VMware guest optimization: Linux

In an effort to squeeze every bit of performance and achieve maximum efficiency out of our vSphere farm, I came across adjusting "ticks" in recent kernel releases. As far as I understand it, ticks are the method in which the CPU(s) query the kernel activity. The more the ticking, the more the checking. Ticks can be favorable for desktop installations such as a user moving the mouse while compiling a program. Compiling is processor intensive but because of the ticks, the CPU looks for the mouse movement in order to fluidly paint the movement across the screen.

Most server installations don't use a mouse often. Therefore, the treadoff may be less variable but the kernel is able to process jobs longer. A side effect, among many, is less power consumption because the kernel isn't constantly nagging the processor(s). It is recommended that Linux VMs employ some sort of tick managment to reduce the activity. Here is a link from VMware showing the various distros that support tick management and how to enable it.

I changed a test CentOS VM and the results were interesting. Check out the idle CPU prior to reboot(spiked activity) and after. Changing this in 1 - 2 VMs, may not yield much for results. However, across 15-30 per host, as we consistently run on our hosts in the farm, we can gain back some needed processing powa!

Thursday, July 23, 2009

Apple's Time Machine brought down by Alex's Voice

I have been toiling with Apple's Time Machine backup software for sometime. I use a MacBook Pro as my primary workstation for work. On paper, Time Machine looks righteous. It snapshots your disk(s) periodically and lets you restore to certain points of time. YMMV depending on how much disk you have for a backup.

I've only gotten it to work once then it died and never worked again. I couldn't find a resolution within a couple hours so I gave up. My mac is becoming less and less reliable these days, it seems. I've been inclined to get it working again. My hope is that this problem has been flushed out in the forums or through updates since the last time I tried about a year ago. NOPE! Like a Volkswagen door handle, its still broken. I let it run and attempted to find out what files it hung up on. Low and behold, it was Alex's voice from the speech synthesizer. I speculate it is corrupt. Interesting note found here. This is the largest file in Leopard. Nice. Incidently, the OS weighs in @ around 10gb. After this, Time Machine appeared to run. Let's see if it works on subsequent backups or if pukes again.

Wednesday, July 22, 2009

VMware VDR, presently, is junk

What else can I say. VMware really messed this one up. Its released as GA, but it isn't ready for beta. It flat out doesn't work. Every aspect of it. However, I was able to successfully import the OVF and get it installed with an IP. I added CIFS as well as local datastores. Neither now work on 1.0.1. So, I have a useless appliance in the farm.
I had hight hopes for this product, hopefully they fix it fast before others start to try to deploy this in production.
Until then, VCB it is.