Linux timekeeping in a virtualized machine

[Varun]

We are running SLES 10 SP2 with kernel 2.6.16.60-0.33 in a VMware environment. We are having some issues with NTP, and VMware recommends using kernel 2.6.22 as it supports "tickelss timekeeping"

We can not update our kernel at this time (Quality Control etc) and I was wondering if anyone knows what timekeeping model 2.6.16 uses?

Thanks!

 

[Nothinman]

Tickful? There's a pretty decent PDF out there from VMware on dealing with timekeeping in guests.

 

[Brazen]

you shouldn't be using ntp to keep time in guest virtual machines. Install ntpd on the host only, then install VMWare Tools in the guests and enable VMWare's Time Sync.

Originally posted by: Nothinman
Tickful?

Touche

 

[GhettoFob]

Originally posted by: Nothinman
Tickful? There's a pretty decent PDF out there from VMware on dealing with timekeeping in guests.

linky

 

[Varun]

Originally posted by: Brazen
you shouldn't be using ntp to keep time in guest virtual machines. Install ntpd on the host only, then install VMWare Tools in the guests and enable VMWare's Time Sync.

Originally posted by: Nothinman
Tickful?

Touche

Actually for Linux guests that is not recommended (although we use it for our Windows guests). According to VMware:
http://kb.vmware.com/selfservi...yKC&externalId=1006427

"Note: In all cases use NTP instead of VMware Tools periodic time synchronization. Also, you may need to open the firewall (UDP 123) to allow NTP traffic. "

They actually recommend to disable the VMware Tools time sync, although the host must be kept in time sync as well for VMotion because when you do a VMotion it syncs the time to the host regardless of if you have the time sync enabled or not.

I found the answer to my question on a blog Tickless timekeeping was added to Linux in 2.6.22. The recommended kernel for our situation (SLES 10 SP2 on ESXi 4) is apparently being killed off with the death of VMware VMI...