CentOS 5 :: Get Rid Of Virtual Clock And Use Physical Clock?
Sep 2, 2011
I had cloned a centos 5.6 installation from virtualbox virtual machine to physical box. Everything work fine. However, the time showing in os using date command differs from bios time by roughly 4 hours. I am running ntp services which sync the time with another centos server on the network. It appears that some services are using virtual clock and some use physical clock. How do I get rid of virtual clock and only use physical clock?
I'm using a very simple conky script to diplay the date and time on my desktop. I've noticed that he conky clock is a few seconds early compared to the time displayed in the right hand side of the top panel (Natty). I guess both displays are based on the same "internal" time, so I'm left wondering how this could happen, and how to sync back the clocks.
It seems that Conky is in sync with the system date, while the panel clock is 2 seconds late (on my system). Checked with while true; do date; sleep 0.1; done
I am running a LAMP system with CentOS 5.4.The clock just automatically shifted backwards by 19 hours and 30 minutes crippling some of my reports and probably damaging something else along the way.The router supplying IP to this server is a DD-WRT and shows proper time.By the way what does that mean? time drifted by that 33.667 ms?
I try to setup a HPC cluster with CentOS 5.5. But now there is no Internet connection available in the room where the hardware is located so I set up ntpd server using synchronization with local clock (maybe I do something wrong). Here is my ntp.conf file on a master node (the master node has IP 10.0.1.1, a file server has IP 10.0.1.2 and compute nodes are 10.0.1.3..10.0.1.11, comments are omitted):
I am trying to install vmware server on CentOS: In vmware installation guide it says before intalling:
Before you begin, read the following notes and make adjustments to your host system: The realÉtime clock function must be compiled in your Linux kernel. The parallel port PCstyle hardware option (CONFIG_PARPORT_PC) must be built and loaded as a kernel module (that is, it must be set to m when the kernel is compiled).
I'm having a problem with the time on one of my servers jumping forward into the future. We run serveral CentOS 5.4 servers running Xen, some up to date and some a little older. The one in question is running 2.6.18-164.el5xen, with xen-libs-3.0.3-94.el5_4.2 and xen-3.0.3-94.el5_4.2. On this server are several Xen virtual machines, also running CentOS 5.4 with kernel 2.6.18-164.el5xen. One in particular has problems with the clock keeping proper time.
We use NTP (ntpd) to sync time to a central server in the company. Our NTP set-up works fine, and we have problems on only a couple of servers out of many. The problem I see is that one one particular Xen virtual machine, the clock will suddenly jump forward into the future, usually by several minutes but once by more than an hour. This has obvious implications for software running on the machine. Software such as Oracle grid control agent will restart itself under the (incorrect) assumption that it has been hung for several minutes with no activity. Oracle database will cope gracefully, but applications that refer to the clock will be confused.
We detect these time jumps because we have Nagios checking the clock on each host against the centralised time server (Nagios's check_ntp plugin). Nagios will suddenly report a clock offset that is miles into the future. Following the time jump, ntpd on the host in question will re-sync the time. Ntpd keeps the time steady, ticking just a few milliseconds per second until real time catches up with the server. i.e. Nagios will report the time as being 10 minutes ahead, then a minute later the host will be 9 minutes ahead, and then a further minute later the host will be 8 minutes ahead of real time. The clock on the host stays running very slow until it eventually is correct.
I've read several write ups on how to convert a physical linux box to a virtual one, but have yet to do it. I've tried a few times just playing around with no success. Generally I use VMware ESX as my host of choice, but am open to citrix's XEN (as citrix presentation server is my day job). I run 3 websites out of the house (on junk left over desktop.. can't believe I've had such good (lucky) uptime). One of the sites was particularly difficult to set up, so I'd rather not ahve to do it over again. It's built on OScommerce (LAMP).. so it's a database server as well come to think of it. So.. what have you tried to convert with/to?
I am encountering some problems regarding CentOS 5 and I am going to kindly ask your help in debugging further what is happening. I will give as much information as possible about the setup. Here we go. We use on one server of our servers, GOautodial, an inbound/outbound call center application, that it's installed on a CentOS 5.5 (Final).
# cat /etc/*release* cat: /etc/lsb-release.d: Is a directory CentOS release 5.5 (Final) GoAutoDial CE 2.0 # uname -a Linux xxxxx.com 2.6.18-194.8.1.el5.goPAE #1 SMP Fri Jul 30 05:30:57 EDT 2010 i686 i686 i386 GNU/Linux
When installing I perhaps mistakingly told Fedora it should use the BIOS clock and now it shows the wrong time, 1 hour ahead of my time-zone GMT+0. If I try and go to the preferences and set the time the 'Advanced Options' one of which I need are grayed out, I need the 'Use local time source' option to be unchecked. Could somebody tell me a workaround or the command-line commands to tell it not to do this anymore?
I tried to adjust my system clock to daylight savings time, but now everytime I restart the computer it's reset. For example, I set the clock to 11:40 AM, Mon. 15 Feb. Upon restart, it's now 12:05 AM, Tue. 16 Feb. I've readjusted the clock several times, and it resets at every reboot.
Today I missed class because my clock was an hour slow. The cause of this seems to be because the windows time service wasn't switched on. Seems to work fine now. Why does windows not use the hardware clock on the motherboard? What does Linux do?
I've finally returned to Ubuntu after leaving it in 2005 because of compatibility issues, but now I'm back and am hoping to stay. My experience with Ubuntu has been great by far and I can safely say that it has improved since '05. Anyway, I'm just wanting to fix this minor little occurrence I just had. You see, the Ubuntu clock and weather isn't appearing anymore. It was there and I don't even remember seeing it removed until now. I don't recall doing anything other than browse the web at the moment and I do recall the time being there before I did some surfing. Anyway, My name is still listed in the upper-right corner of the screen still. Just not the time. Did anyone else have this problem and know of a fix?
I've been running a fedora server for over a year now, and has seen some very strange issue, that really make it uncomfortable to use, and that I cannot manage to solve easily.
The problem is as follow : sometimes (every 20-30 minutes or so : this time is quite random), the server completely hangs.
I'm using it mainly remotely, through ssh and nfs. What I see when it "hangs" is the following: -no ping response -nfs stalled -ssh sessions hangs (for example, if I run a "top" command", it just isn't updated anymore -disk activity led stays completely off (in normal activity, it is almost always blinking, even due to "internal" server activities, so network disconnection doesn't explain that either)
The most strange thing is that, to resume it, I basically have 3 options : wait (sometimes few tens of seconds, usually between 2 and 4 minutes!), just hit a key on the keyboard!, or do something like un/plugging any king of usb peripheral (which makes me think of some interruption mechanism that is stalled).
When it "wakes up", I see my "top" session over ssh suddenly being quickly updated hundreds of times (for all it has not received during the "pause"), ping says that the packets have actually all been received (with long times, for example, packet 1 : 80xxxms, packet 2 : 79xxxms, packet 3 : 78xxxms..... packet 79 : 1xxxms, packet 80 : 0.xxxms), the disk is quite overloaded for a few seconds, and everything is back at normal!
Furthermore, I think this i related, but my clock drifts for few hours per day (3 holding minutes every 20-30 minutes makes me think there is some relation!) I tried to set up ntpd to compensate it, but sometimes the suspensions are just too long, and I ended up with
Code: Nov 27 01:22:36 server ntpd: 0.0.0.0 0617 07 panic_stop +1203 s; set clock manually within 1000 s and ntpd dies...
You'll ask me to have a look at the log, which I did by
But when the suspension happens, there is absolutely nothing new in all those files!
Version information :
I said in the title "F13-F14", because I already had the problem with F13, but after some time it disappeared (I may have changed some configuration, I have to admit...). I still have a backup of the "/etc" tree of that "working" F13.
The hardware for F13[working] and F14[not_working] is the same : Phenom II X4 on an ASUS M3N78 PRO, data on raid 10, system on separated SATA disk, 8Gb RAM, some qemu vms running (between 4 and 6).
There is no clock on my panel after the 11.3 install. I don't get it. I unlock the widgets and there is a digital clock there, but I cannot drag it to the panel, only the desktop. So I suppose there is another way of adding it. The standard clock is not a widget?
My laptop's clock (Acer Extensa 5220) seems to be slow. I've corrected it 5 minutes forward last week and now have just corrected minute forward again. Is there a program [apart from time servers] to correct clock properly, for example, by shifting it a bit every hour? Is there already a program to put it to crontab or I should hack up a script? Or I should check more things?
I have found that HW clock is right, but system time is slow: about a second each 2.1 hours. root@vi-notebook:~# dmesg | egrep 'clock|unstable' [ 0.103785] Switching to clocksource tsc [ 0.265274] Marking TSC unstable due to TSC halts in idle [ 0.265514] Switching to clocksource acpi_pm [ 1.321408] rtc_cmos 00:09: setting system clock to 2010-10-30 00:10:48 UTC (1288397448) Is placing "hwlock --hctosys" to crontab a right thing?
While dual-booting Windows and Linux, Linux sets the system time to UTC, so Windows thinks it's midnight near mid-morning. Is there any other way to tell Windows to use UTC? I've seen the registry tweak proposed here and other places. This does not work on my computer (Windows 7 32-bit).For reference, the registry entry is this:HKEY_LOCAL_MACHINESYSTEMCurrentControlSetControlTimeZoneInformation]"RealTimeIsUniversal"=dword:00000001