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On 2013-01-17, Stroller <stroller@××××××××××××××××××.uk> wrote: |
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> |
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> On 16 January 2013, at 16:43, Grant Edwards wrote: |
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> |
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>> I'm having problems with one of my Gentoo systems who's motherboard |
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>> clock is a little slow. When the system comes up, the system time is |
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>> set from the motherboard clock. If that's slow, something in the init |
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>> system seems to panic because some file or other has a timestamp in |
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>> the future. |
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> |
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> You've had lots of other suggestions here, but I think this is |
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> handled fine if you add ntp to the default runlevel (and assuming the |
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> system can connect to the net). |
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It doesn't help problems that occur before ntpd has started and had a |
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chance to slew the clock. By default, ntpd doesn't seem to want to do |
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a step correction to fix large clock errors on startup (there's |
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probably an option for that). |
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|
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FWIW, I recently identified one rather obscure CMOS-clock-related |
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problem scenario (this isn't what happened the other day, but it did |
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waste about half a day a few months back): |
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|
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1) Your CMOS clock is ahead of the "real" time by several hours for |
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some reason. There are a number of ways this can happen: |
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dual-booting between systems that disagree over UTC vs localtime |
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for the CMOS clock, broken ntpd config, mismanaged timezone |
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settings, etc. |
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|
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2) Kernel comes up and sets system time from CMOS clock. |
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|
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3) Root filesystem gets fsck'ed because it's been mounted 28 times, |
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and filesystem meta-data gets timestamp that is actually several |
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hours in the future. |
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4) System reboots after fsck is finished. |
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5) Before the recently fsck'ed filesystem gets mounted, the CMOS |
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clock gets reset to the correct time (by dual booting, booting |
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from a rescue CD, or by simply running the BIOS setup and fixing |
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it). |
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|
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6) The system boots again, and when it tries to mount the root |
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filesystem, the filesystem meta-data has a timestamp that's in the |
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future so the ext3 code in the kernel refuses to mount it. |
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|
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7) You futz around verifying that you have a good root fs backup, |
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looking at S.M.A.R.T logs and all sorts of other irrelevant things |
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for several hours trying to figure out what's wrong. |
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|
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8) The universe catches up to the filesystem meta-data timestamp, and |
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suddenly, mysteriously, everything works fine. |
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|
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-- |
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Grant Edwards grant.b.edwards Yow! You mean you don't |
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at want to watch WRESTLING |
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gmail.com from ATLANTA? |
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