iSOblog

as i mentioned in my last post, pascal-schwarz.ch (web- and mailserver, you’re using it right now) is now hosted inside a virtual machine on my ovh root server.

it works really nice generally, however i must also point out that this machine doesn’t generate too much load. it might be a problem to use vmware if the guest would really have a lot of IO operations to perform. but as long as it doesn’t do so, i like the simple way do administrate the virtual machine and the possibility to watch the boot operation in case there would be a problem.

i had to fix a little problem with the time-keeping of the guest. the clock inside the virtual machine was running too slow (about 0.5 seconds delay per minute which leads to a delay of around 12 minutes per day…). i did not want to install the virtual machine guest tools, as i thought that it has to be possible to fix the problem without special tools.

so i tried to sync the clock regularily using ntpd, which works usually really nice. however, to my surprise, this did nearly do no change. reading through the vmware-guide for time-keeping, i changed some options inside my (guest-)kernel which did also not lead to the wanted effect. however, it might be that those options are needed, so i’ll post them here:

• deactivate the option “tick-less kernel”
• deactivate preemption (on a server not needed anyway)
• make sure the guest doesn’t have a higher tickrate than the host (my host has 250hz while the guest has 100hz)

so i did some more tricks that vmware suggests, adding parameters to my kernel – here’s my menu.lst:

using these kernel-parameters in conjunction with ntpd, the clock now runs absolutely exact inside the virtual machine.