ankush grover wrote: > Earlier this server was syncing time through ntp daemon and below is > the ntp.conf file. Now I have set a cronjob which sync the time with Best not to run NTP inside a ESX VM. I've never gotten NTP to sync inside of VMware outside of a kernel with VMI enabled (no versions of RHEL support VMI at this time as far as I know). What I do for my ~40 ESX/ESXi hosts: - Have your ESX hosts sync to a good NTP server - Make sure vmware tools is installed and running correctly (/etc/init.d/vmware-tools status) - Enable time sync for your guest, either via the UI or via this command in the guest(I have this command run in cron every 5 minutes as I have seen for some reason time sync turn itself off: /usr/sbin/vmware-guestd --cmd "vmx.set_option synctime 0 1" - On top of all of that I have another cron set to run ntpdate every 5 minutes against a local NTP server: /usr/sbin/ntpdate `cat /etc/ntp/step-tickers | grep -v \#` For providing NTP services themselves, currently I run 3 VMs at each site with Fedora 8 with VMI enabled for the guest VM (the kernel in FC8 supports VMI, I suspect newer Fedoras work fine too I just have no reason to change right now). And I have these FC8 VMs sync to internet hosts(mainly time.nist.gov) so my internal ESX and other systems can sync against them(they are load balanced behind a F5 BigIP). from FC8 kernel log: VMI: Found VMware, Inc. Hypervisor OPROM, API version 3.0, ROM version 1.0 vmi: registering clock event vmi-timer. mult=9483317 shift=22 Booting paravirtualized kernel on vmi vmi: registering clock source khz=2260999 Time: vmi-timer clocksource has been installed. I currently run roughly 400 VMs this way and don't have any noticeable time-related issues. nate