HI, guys Recently,I met a problem. Xen''s version: 3.4.3 guest os:redhat 4.8 32bit And xen.independent_wallclock = 1 has been set. The time of guest os change to be fast suddenly, about 2000 second. because the change is too wild, ntp didn''t sync to the ntp server''s time. my application is dependent on the systme time. And this occurs a lot of times. I don''t know which situation will cause this problem. Does anyone can help me ? thank you! sincerely chieu
On Mon, 9 Apr 2012, Chieu wrote:> HI, guys > > Recently,I met a problem. > Xen''s version: 3.4.3 > guest os:redhat 4.8 32bit > > And xen.independent_wallclock = 1 has been set. > > The time of guest os change to be fast suddenly, about 2000 second. > because the change is too wild, ntp didn''t sync to the ntp server''s time. > > my application is dependent on the systme time. And this occurs a lot of times. > > I don''t know which situation will cause this problem.I have seen this with many different versions of Redhat 32-bit guests (4.x and 5.x) on Xen from 3.1 upwards. Never found a fix besides migrating all my guests to 64-bit. independent_wallclock is better than not, but I see exactly the same problem that the clock jumps forward by 20-40 minutes and then just holds there until real time catches up to it. Steve Timm> > Does anyone can help me ? > > thank you! > > sincerely > > chieu > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xen.org > http://lists.xen.org/xen-users >------------------------------------------------------------------ Steven C. Timm, Ph.D (630) 840-8525 timm@fnal.gov http://home.fnal.gov/~timm/ Fermilab Computing Division, Scientific Computing Facilities, Grid Facilities Department, FermiGrid Services Group, Group Leader. Lead of FermiCloud project.
Clock drift was a really big problem with VMware workstation/server (at least on AMD platforms) until hardware-assisted virtualization came around and seemingly fixed the problem. Are you running PV guests? If so, you might try switching them to HVM (which could be a non-trivial task!) to work around the issue. Just a suggestion, though. No clue if it''ll work :P On Mon, Apr 9, 2012 at 10:04 AM, Steven Timm <timm@fnal.gov> wrote:> On Mon, 9 Apr 2012, Chieu wrote: > >> HI, guys >> >> Recently,I met a problem. >> Xen''s version: 3.4.3 >> guest os:redhat 4.8 32bit >> >> And xen.independent_wallclock = 1 has been set. >> >> The time of guest os change to be fast suddenly, about 2000 second. >> because the change is too wild, ntp didn''t sync to the ntp server''s time. >> >> my application is dependent on the systme time. And this occurs a lot of >> times. >> >> I don''t know which situation will cause this problem. > > > I have seen this with many different versions of Redhat 32-bit > guests (4.x and 5.x) on Xen from 3.1 upwards. Never found a fix besides > migrating all my guests to 64-bit. independent_wallclock is > better than not, but I see exactly the same problem that the clock > jumps forward by 20-40 minutes and then just holds there until > real time catches up to it. > > Steve Timm > > > >> >> Does anyone can help me ? >> >> thank you! >> >> sincerely >> >> chieu >> >> _______________________________________________ >> Xen-users mailing list >> Xen-users@lists.xen.org >> http://lists.xen.org/xen-users >> > > ------------------------------------------------------------------ > Steven C. Timm, Ph.D (630) 840-8525 > timm@fnal.gov http://home.fnal.gov/~timm/ > Fermilab Computing Division, Scientific Computing Facilities, > Grid Facilities Department, FermiGrid Services Group, Group Leader. > Lead of FermiCloud project. > > > _______________________________________________ > Xen-users mailing list > Xen-users@lists.xen.org > http://lists.xen.org/xen-users
thank you for help. The special is when the time jumps forward， then the time won't change and keep the time always。 for example, the time jumps to 4:00 from 3:30， then the time keeps 4:00。 2012/4/9 Steven Timm <timm@fnal.gov>:> On Mon, 9 Apr 2012, Chieu wrote: > >> HI, guys >> >> Recently,I met a problem. >> Xen's version: 3.4.3 >> guest os:redhat 4.8 32bit >> >> And xen.independent_wallclock = 1 has been set. >> >> The time of guest os change to be fast suddenly, about 2000 second. >> because the change is too wild, ntp didn't sync to the ntp server's time. >> >> my application is dependent on the systme time. And this occurs a lot of >> times. >> >> I don't know which situation will cause this problem. > > > I have seen this with many different versions of Redhat 32-bit > guests (4.x and 5.x) on Xen from 3.1 upwards. Never found a fix besides > migrating all my guests to 64-bit. independent_wallclock is > better than not, but I see exactly the same problem that the clock > jumps forward by 20-40 minutes and then just holds there until > real time catches up to it. > > Steve Timm > > >> >> Does anyone can help me ? >> >> thank you! >> >> sincerely >> >> chieu >> >> _______________________________________________ >> Xen-users mailing list >> Xen-users@lists.xen.org >> http://lists.xen.org/xen-users >> > > ------------------------------------------------------------------ > Steven C. Timm, Ph.D (630) 840-8525 > timm@fnal.gov http://home.fnal.gov/~timm/ > Fermilab Computing Division, Scientific Computing Facilities, > Grid Facilities Department, FermiGrid Services Group, Group Leader. > Lead of FermiCloud project._______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users
On Tue, 10 Apr 2012, Chieu wrote:> thank you for help. > > The special is when the time jumps forward， then the time won''t change > and keep the time always。 > > for example, the time jumps to 4:00 from 3:30， then the time keeps 4:00。 >Yes, I see exactly the same problem. It has been there for years. Steve Timm> > > 2012/4/9 Steven Timm <timm@fnal.gov>: >> On Mon, 9 Apr 2012, Chieu wrote: >> >>> HI, guys >>> >>> Recently,I met a problem. >>> Xen''s version: 3.4.3 >>> guest os:redhat 4.8 32bit >>> >>> And xen.independent_wallclock = 1 has been set. >>> >>> The time of guest os change to be fast suddenly, about 2000 second. >>> because the change is too wild, ntp didn''t sync to the ntp server''s time. >>> >>> my application is dependent on the systme time. And this occurs a lot of >>> times. >>> >>> I don''t know which situation will cause this problem. >> >> >> I have seen this with many different versions of Redhat 32-bit >> guests (4.x and 5.x) on Xen from 3.1 upwards. Never found a fix besides >> migrating all my guests to 64-bit. independent_wallclock is >> better than not, but I see exactly the same problem that the clock >> jumps forward by 20-40 minutes and then just holds there until >> real time catches up to it. >> >> Steve Timm >> >> >>> >>> Does anyone can help me ? >>> >>> thank you! >>> >>> sincerely >>> >>> chieu >>> >>> _______________________________________________ >>> Xen-users mailing list >>> Xen-users@lists.xen.org >>> http://lists.xen.org/xen-users >>> >> >> ------------------------------------------------------------------ >> Steven C. Timm, Ph.D (630) 840-8525 >> timm@fnal.gov http://home.fnal.gov/~timm/ >> Fermilab Computing Division, Scientific Computing Facilities, >> Grid Facilities Department, FermiGrid Services Group, Group Leader. >> Lead of FermiCloud project. >------------------------------------------------------------------ Steven C. Timm, Ph.D (630) 840-8525 timm@fnal.gov http://home.fnal.gov/~timm/ Fermilab Computing Division, Scientific Computing Facilities, Grid Facilities Department, FermiGrid Services Group, Group Leader. Lead of FermiCloud project. ---511486384-1715348015-1334066648=:11701 Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-users mailing list Xen-users@lists.xen.org http://lists.xen.org/xen-users ---511486384-1715348015-1334066648=:11701--