samba - May 2003 - How 'accurate' is time sync on the samba server?

Just as the subject states, how close and accurate can time synchronization 
be with Samba as a PDC and Windows Clients connecting to the PDC with net time?

I have setup a logon script, so when all Win2k clients connect to the PDC, 
they will receive the logon script and use the PDC as their time server.

What I have noticed in my testing is that it is not entirely 100% accurate? 
For example, I noticed about a 35 second difference  between the PDC and a 
test client.

I have set time server =yes
I set the script to be:

net time \\sambatest /set /yes

I made sure the logon.bat file is a MS-DOS style file.

Thoughts?

Jason

On Mon, 5 May 2003, Jason Williams wrote:
> Just as the subject states, how close and accurate can time synchronization
> be with Samba as a PDC and Windows Clients connecting to the PDC with net
time?
What you are seeing is par for the course.

If you want tighter time synchronization I would suggest that you install
on each client an NTP service that syncs with atomic clocks.

- John T.
>
> I have setup a logon script, so when all Win2k clients connect to the PDC,
> they will receive the logon script and use the PDC as their time server.
>
> What I have noticed in my testing is that it is not entirely 100% accurate?
> For example, I noticed about a 35 second difference  between the PDC and a
> test client.
>
> I have set time server =yes
> I set the script to be:
>
> net time \\sambatest /set /yes
>
> I made sure the logon.bat file is a MS-DOS style file.
>
> Thoughts?
>
> Jason
>
>
-- 
John H Terpstra
Email: jht@samba.org

Well, as it stands right now, what I noticed is that the server may be at 
4:05:15
At the same time, the test client was at 4:04:45. Even though it is roughly 
a 30-35 second time difference, I would prefer it to be a little closer. 
Maybe around 10-15 second time difference, if possible.

I thought about installing a client NTP service, such as one from 
http://www.analogx.com

Probably best to install clients on each one I would imagine then?

Jason

At 11:27 PM 5/5/2003 +0000, you wrote:
>On Mon, 5 May 2003, Jason Williams wrote:
>
> > Just as the subject states, how close and accurate can time
synchronization
> > be with Samba as a PDC and Windows Clients connecting to the PDC with 
> net time?
>
>What you are seeing is par for the course.
>
>If you want tighter time synchronization I would suggest that you install
>on each client an NTP service that syncs with atomic clocks.
>
>- John T.
>
> >
> > I have setup a logon script, so when all Win2k clients connect to the
PDC,
> > they will receive the logon script and use the PDC as their time
server.
> >
> > What I have noticed in my testing is that it is not entirely 100%
accurate?
> > For example, I noticed about a 35 second difference  between the PDC
and a
> > test client.
> >
> > I have set time server =yes
> > I set the script to be:
> >
> > net time \\sambatest /set /yes
> >
> > I made sure the logon.bat file is a MS-DOS style file.
> >
> > Thoughts?
> >
> > Jason
> >
> >
>
>--
>John H Terpstra
>Email: jht@samba.org

I'm using this one on all my workstations: 
http://www.eecis.udel.edu/~ntp/ntp_spool/html/hints/winnt.html

We have about 20 machines, so instead of imposing that kind of load on some
other site's time server I set up three of our systems (servers that
don't
get rebooted much) as NTP servers, each with the two other servers in the
pool and two external time servers as peers.  (This is the sort of
configuration recommended in the NTP docs.)  The workstations then use those
three servers for synchronization.  The results have been really excellent.
It took a few hours for them to converge, but now all our computers are
usually within 10 ms of each other unless they've just been rebooted.  You
don't have to do anything this elaborate, but the advantage of having three
time sources is if one machine's clock goes off, the other two will outvote
it and the clients will ignore it.

One word of warning: Microsoft security update Q328310 seems to interact
with this service on NT 4.0 and cause blue screens.  This is a problem
Microsoft has acknowledged, which leads me to believe it's not strictly a
function of the NTP service.  I haven't seen the problem on Windows 2000
Professional.
> -----Original Message-----
> From: Jason Williams [mailto:jwilliams@courtesymortgage.com]
> Sent: Monday, May 05, 2003 7:42 PM
> To: John H Terpstra
> Cc: samba@lists.samba.org
> Subject: Re: [Samba] How 'accurate' is time sync on the samba
server?
> 
> 
> Well, as it stands right now, what I noticed is that the 
> server may be at 
> 4:05:15
> At the same time, the test client was at 4:04:45. Even though 
> it is roughly 
> a 30-35 second time difference, I would prefer it to be a 
> little closer. 
> Maybe around 10-15 second time difference, if possible.
> 
> I thought about installing a client NTP service, such as one from 
> http://www.analogx.com
> 
> Probably best to install clients on each one I would imagine then?
> 
> Jason