> yeah, i''m already doing that, I was just saying, it *seemed* > like they were getting their time from domain0, and weren''t > actually changing their own clocks in accordance with syncing > with the same ntpd server.> especially since they''re all off by exactly the same amount > ... and running ntpdate doesn''t seem to have any effect whatsoever?If you don''t run ntp in the domU''s, it should just work. If you want to run ntp in the domU, try: echo 1 > /proc/sys/xen/independent_wallclock I guess we could be smarter about this, and make the wall clock independent automatically if someone does an adjtimex syscall. Anyone got any comments on this? Ian> On Thu, 12 May 2005, Fernando Maior wrote: > > > On 5/12/05, andrew mathes <amathes@backnine.org> wrote: > >> don''t the DomU''s just get their time from DomO? Ie. ... > even if they > >> weren''t running ntp they''d always be synced with whatever DomO > >> thought about system time? > >> > >> Maybe i''m way off > >> > >> On Thu, 12 May 2005, Alex Tomkins wrote: > >> > >>> On Thu, May 12, 2005 at 10:42:53AM -0700, andrew mathes wrote: > >>>> So, from what it looks like (on my servers and the docs), all my > >>>> domains get their time from DomO. Which I have setting itself > >>>> through NTP, and the dom0 looks good. However, All of > the domains > >>>> are 1.5 seconds off, and won''t ntp themselves on, also, an > >>>> identical server, all the domains are > >>>> .768 seconds off (off of the server i''m ntping to) , but both > >>>> domO''s are withing (.02) and seem to narrow in as NTP is > supposed to. > >>>> > >>>> So, question is, 1) what is going on here, and 2) can > anything be > >>>> done about it? > >>> Are you using OpenNTPD by any chance? > >>> My machines suffered from inaccurate clocks in DomU''s, > even though > >>> the clock was very accurate in Dom0. Switching to regular ntpd > >>> solved this, DomU immediately used the correct time > shortly after starting ntpd. > >>> -- > >>> Alex Tomkins <tomkins@darkzone.net> > > > > Andrew, > > > > Please remember, you allways shoult treat each virtual > machine like a > > completely separated host! So far, you shoul configure ntpd to get > > time from -possibly- the same host as you dom0 is getting time. Try > > that. It won''t hurt :) And I bet you will feel happy with > the result > > :) > > > > -- > > Bye, > > Fernando Maior > > LPIC/1 31908 > > > > _______________________________________________ > > Xen-users mailing list > > Xen-users@lists.xensource.com > > http://lists.xensource.com/xen-users > > > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Ian Pratt wrote:> > > > >>yeah, i''m already doing that, I was just saying, it *seemed* >>like they were getting their time from domain0, and weren''t >>actually changing their own clocks in accordance with syncing >>with the same ntpd server. >> >> > > > >>especially since they''re all off by exactly the same amount >>... and running ntpdate doesn''t seem to have any effect whatsoever? >> >> > >If you don''t run ntp in the domU''s, it should just work. > >If you want to run ntp in the domU, try: > echo 1 > /proc/sys/xen/independent_wallclock > >I guess we could be smarter about this, and make the wall clock >independent automatically if someone does an adjtimex syscall. Anyone >got any comments on this? > >Ian > > > > >>On Thu, 12 May 2005, Fernando Maior wrote: >> >> >> >>>On 5/12/05, andrew mathes <amathes@backnine.org> wrote: >>> >>> >>>>don''t the DomU''s just get their time from DomO? Ie. ... >>>> >>>> >>even if they >> >> >>>>weren''t running ntp they''d always be synced with whatever DomO >>>>thought about system time? >>>> >>>>Maybe i''m way off >>>> >>>>On Thu, 12 May 2005, Alex Tomkins wrote: >>>> >>>> >>>> >>>>>On Thu, May 12, 2005 at 10:42:53AM -0700, andrew mathes wrote: >>>>> >>>>> >>>>>>So, from what it looks like (on my servers and the docs), all my >>>>>>domains get their time from DomO. Which I have setting itself >>>>>>through NTP, and the dom0 looks good. However, All of >>>>>> >>>>>> >>the domains >> >> >>>>>>are 1.5 seconds off, and won''t ntp themselves on, also, an >>>>>>identical server, all the domains are >>>>>>.768 seconds off (off of the server i''m ntping to) , but both >>>>>>domO''s are withing (.02) and seem to narrow in as NTP is >>>>>> >>>>>> >>supposed to. >> >> >>>>>>So, question is, 1) what is going on here, and 2) can >>>>>> >>>>>> >>anything be >> >> >>>>>>done about it? >>>>>> >>>>>> >>>>>Are you using OpenNTPD by any chance? >>>>>My machines suffered from inaccurate clocks in DomU''s, >>>>> >>>>> >>even though >> >> >>>>>the clock was very accurate in Dom0. Switching to regular ntpd >>>>>solved this, DomU immediately used the correct time >>>>> >>>>> >>shortly after starting ntpd. >> >> >>>>>-- >>>>>Alex Tomkins <tomkins@darkzone.net> >>>>> >>>>> >>>Andrew, >>> >>>Please remember, you allways shoult treat each virtual >>> >>> >>machine like a >> >> >>>completely separated host! So far, you shoul configure ntpd to get >>>time from -possibly- the same host as you dom0 is getting time. Try >>>that. It won''t hurt :) And I bet you will feel happy with >>> >>> >>the result >> >> >>>:) >>> >>>-- >>>Bye, >>>Fernando Maior >>>LPIC/1 31908 >>> >>>_______________________________________________ >>>Xen-users mailing list >>>Xen-users@lists.xensource.com >>>http://lists.xensource.com/xen-users >>> >>> >>> >>_______________________________________________ >>Xen-users mailing list >>Xen-users@lists.xensource.com >>http://lists.xensource.com/xen-users >> >> >> > >_______________________________________________ >Xen-users mailing list >Xen-users@lists.xensource.com >http://lists.xensource.com/xen-users > > >Something to think about, if the vms are syncing off the Dom0 then there would be no way to configure the guest systems in different time zones. To me that would be a plus with the vm''s. -- Paul Edgar Content Delivery System IBM/Austin javaoops@us.ibm.com No trees were destroyed in the sending of this message, however, a significant number of electrons were terribly inconvenienced. _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
Ian Pratt wrote:> > > > >>yeah, i''m already doing that, I was just saying, it *seemed* >>like they were getting their time from domain0, and weren''t >>actually changing their own clocks in accordance with syncing >>with the same ntpd server. >> >> > > > >>especially since they''re all off by exactly the same amount >>... and running ntpdate doesn''t seem to have any effect whatsoever? >> >> > >If you don''t run ntp in the domU''s, it should just work. > >If you want to run ntp in the domU, try: > echo 1 > /proc/sys/xen/independent_wallclock > >I guess we could be smarter about this, and make the wall clock >independent automatically if someone does an adjtimex syscall. Anyone >got any comments on this? > >Ian > > >Don''t auto-detect based on adjtimex. It would be too easy and too confusing to accidentally make such a call once, and then not realize that you would no longer be auto-synchronized. Instead, make independent_wallclock be a config file option that is overridable by proc. -Tupshin _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
yes, changing this value allowed domU independent syncing, thank you very much!! i agree on the config file option if possible ... On Thu, 12 May 2005, Tupshin Harper wrote:> Ian Pratt wrote: > >> >> >> >> >>> yeah, i''m already doing that, I was just saying, it *seemed* >>> like they were getting their time from domain0, and weren''t >>> actually changing their own clocks in accordance with syncing >>> with the same ntpd server. >>> >>> >> >> >> >>> especially since they''re all off by exactly the same amount >>> ... and running ntpdate doesn''t seem to have any effect whatsoever? >>> >>> >> >> If you don''t run ntp in the domU''s, it should just work. >> >> If you want to run ntp in the domU, try: >> echo 1 > /proc/sys/xen/independent_wallclock >> >> I guess we could be smarter about this, and make the wall clock >> independent automatically if someone does an adjtimex syscall. Anyone >> got any comments on this? >> >> Ian >> >> >> > Don''t auto-detect based on adjtimex. It would be too easy and too > confusing to accidentally make such a call once, and then not realize > that you would no longer be auto-synchronized. > > Instead, make independent_wallclock be a config file option that is > overridable by proc. > > -Tupshin >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
anyone know where I should set this so that it stays "1" after reboot? I''m not sure the best way to do this ... thanks a bunch On Thu, 12 May 2005, andrew mathes wrote:> yes, changing this value allowed domU independent syncing, thank you very > much!! > > i agree on the config file option if possible ... > > On Thu, 12 May 2005, Tupshin Harper wrote: > >> Ian Pratt wrote: >> >> > >> > >> > >> > >> > > yeah, i''m already doing that, I was just saying, it *seemed* >> > > like they were getting their time from domain0, and weren''t >> > > actually changing their own clocks in accordance with syncing >> > > with the same ntpd server. >> > > >> > > >> > >> > >> > >> > > especially since they''re all off by exactly the same amount >> > > ... and running ntpdate doesn''t seem to have any effect whatsoever? >> > > >> > > >> > >> > If you don''t run ntp in the domU''s, it should just work. >> > >> > If you want to run ntp in the domU, try: >> > echo 1 > /proc/sys/xen/independent_wallclock >> > >> > I guess we could be smarter about this, and make the wall clock >> > independent automatically if someone does an adjtimex syscall. Anyone >> > got any comments on this? >> > >> > Ian >> > >> > >> > >> Don''t auto-detect based on adjtimex. It would be too easy and too >> confusing to accidentally make such a call once, and then not realize >> that you would no longer be auto-synchronized. >> >> Instead, make independent_wallclock be a config file option that is >> overridable by proc. >> >> -Tupshin >> > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xensource.com > http://lists.xensource.com/xen-users > >_______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
andrew mathes wrote:> anyone know where I should set this so that it stays "1" after reboot? > I''m not sure the best way to do this ...Just add it to your rc.local or equivalent startup script. (It''ll be distribution specific.) -- Andrew Thompson http://aktzero.com/ _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users