Re: Preserving uptime with kexec?

From: Nick Warne
Date: Mon Jul 31 2006 - 11:43:58 EST

Speaking of which, I have submitted a claim to Guiness Book of Records
for my uptime on a lowly 486 box that serves my webpages (via NFS) as
a 'home user' (I am sure business classed machines do better with UPS
etc.). I have posted here twice when it hit 1000 days and then 1500

[nick@486Linux nick]$ uname -a
Linux 486Linux 2.2.13-7mdk #1 Wed Sep 15 18:02:18 CEST 1999 i486 unknown

[nick@486Linux nick]$ last -xf /var/run/utmp runlevel
runlevel (to lvl 3) Sun Oct 14 16:07 - 16:42 (1751+00:34)

The claim has been accepted, and is now in evaluation... so I dunno
what happens next until I hear from them (or how it can be verified
unless someone pops along and I telnet into the box for them).


On 31/07/06, Valdis.Kletnieks@xxxxxx <Valdis.Kletnieks@xxxxxx> wrote:
On Mon, 31 Jul 2006 08:59:13 EDT, Thomas Tuttle said:
> Like many people, I like to brag about how great my uptime is. But like
> many other people, I like to keep my kernel up-to-date with the latest
> and greatest from I recently discovered the magic of kexec,
> which allows me to switch kernels without rebooting for real.
> Unfortunately, kexec resets my uptime when it runs.

The reset of uptime is probably a Good Thing. Consider the case of
a kernel memory leak - you look in /proc/meminfo and find that you've
to lose 64 meg of memory to the leak. Where you start looking for the
leak will depend on whether it's 64 meg lost across 4 weeks since the
last boot, or the 30 minutes since the last boot.

(Speaking as somebody who's run into both classes of leaks...)

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