Re: [CentOS] vmware-time update issues and typematic issues

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rado wrote:
right now system times are off 2 mins after all nite ...yest. that would
have been 10-12hrs. I stopped all ntp or whatever that is...going out to
one of the time servers...just getting time from the host system.

Some hints from the vmware website for 2.6 kernels say to use "clock=pit" kernel option in guests, disable NTP in guests (system clocks in virtual machines are too unstable), and let vmware tools sync the time with the host OS (you can use NTP to sync the time of the host OS with some time source, of course).

If you have both 2.4 and 2.6 kernels running in guests, you'll probably notice that 2.6 kernels are taking 3-4 times more CPU time when the guest is idling. That's because the default frequency of interrupts changed from 100Hz to 1kHz (and that is per CPU) in 2.6 kernels. Placing much more stress on vmware and causing all bunch of problems with it. It's configurable compile time option (you'd need to recompile kernel to change it to the old default). I have one (not really brand new anymore) dual-Xeon machine that runs ESX with 5 2.6 guests and couple of 2.4 guests. When all the guests are idle, they consume about half of the CPU time of one processor. I haven't yet attempted recompiling 2.6 kernel and lowering frequency of interrupts, but it's probably worth trying.
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