Time synchronization problem for VMWare with RAC and Linux setup

Thought this thread might be useful to someone, someday. :)

• Forwarded message ---------- Subject: Re: Time synchronization problem for VMWare with RAC and Linux setup To: Eugene Plagge Cc: Dan Norris, Ben Prusinski

Yeah, IMHO it's best not to involve NTP with VMs. Time sync is a rather complex issue for virtual environments (VMware has had large problems in this area). Here's a great paper on the topic: http://www.vmware.com/pdf/vmware_timekeeping.pdf

For your test RAC cluster the VMware clock sync option should work fine - we used it for all of the workstations during the lab in Chicago and didn't have any problems. You mentioned that the VM's aren't in sync with each other - are they in sync with the server?

On older versions of linux I always used to add the kernel parameter "clock=pit" and this helped with clock drift. You might try that too if you're having drift problems.

-Jeremy

On Tue, Sep 2, 2008 at 3:38 PM, Eugene Plagge wrote:

> Thanks, Dan,
>
> Good tip about using ntp like that. We'll let you know if we discover
> anything else interesting.
>
>
>
> Eugene
>
>
>
>
>
> *From:* Dan Norris
> *Sent:* Tuesday, September 02, 2008 4:23 PM
> *To:* Eugene Plagge; Jeremy Schneider
> *Cc:* Ben Prusinski
> *Subject:* Re: Time synchronization problem for VMWare with RAC and Linux
> setup
>
>
>
> Hi Eugene,
>
> As Ben pointed out, the VMWare Tools should handle the synchronization. If
> there's no internet access from the machines, it is possible to set the
> machines to sync to one another using NTP (as peers) I believe. That way,
> they may both be off of the "real" time, but they should at least be sync'd
> with each other and that should allow you to complete the installation.
>
> In the worst case, if you set the clocks on each node to be the same within
> a few seconds, you should be able to complete the installations
> successfully. In that case, when the nodes reboot, you may have one or the
> other of them fail to join the cluster if the clocks aren't in sync.
>
> Let me know if that doesn't do the trick. Jeremy may also add in his own
> ideas.
>
> Dan
>
>
> On 9/2/08 3:10 PM, "Eugene Plagge" wrote:
>
> Hi, Jeremy and Dan,
> I attended the RAC Attack a few weeks ago. A colleague and I are having a
> problem setting up Linux VM machines.
> The time synchronization does not seem to be working (please see Ben's
> email below). I am having similar problems.
>
> Any hints or avenues we can try?
>
> Thanks very much,
>
>
> ****
>
> *From:* Ben Prusinski
> *Sent:* Tuesday, September 02, 2008 12:30 PM
> *To:* Doug Hahn
> *Cc:* Eugene Plagge
> *Subject:* Time synchronization problem for VMWare with RAC and Linux
> setup
>
>
> Thanks Doug will do.
>
>
>
>
>
> Hello Gene-
>
>
>
> I am having problems with my test 2-node RAC setup for Linux on VMWare. The
> issue is time synchronization for ntp and system clock for both VM machines
> in the cluster. I installed VMWare tools on both Linux VM guest OS machines
> to synchronize the time (via the option in the tools menu) but still they
> are not in sync. This will cause the RAC clusterware installation to fail if
> both nodes are not in sync with each other. Currently, both test VM machines
> do not have internet access so I am not able to use the internet NTP servers
> that are recommended. If you have been able to solve this problem,
> definitely would appreciate your insight and tips.
>
>
>
> Thanks in advance,
>
> Ben
>
>
> **
>

-- 
Jeremy Schneider
Chicago, IL
http://www.ardentperf.com/category/technical

--
http://www.freelists.org/webpage/oracle-l