Re: [gentoo-user] Re: A little light relief from endless problems

[Allan Gottlieb <gottlieb@nyu.edu>]

At Sun, 01 Mar 2009 13:57:30 +0200 Nikos Chantziaras <realnc@arcor.de> wrote:

> Peter Humphrey wrote:
>> As it's Sunday, here's an odd little thing.
>>
>> Not long ago, while booting this machine, four ext3 partitions
>> needed checks on remount count reaching zero. They had been set to
>> 23, 24, 25 and 26 mounts. (I didn't choose the numbers; they were
>> allocated at the time I was creating the file system.)
>>
>> Now, this box does get rebooted, but hardly 23 x 24 x 25 x 26 =
>> 358,800 times all told. At, say, two reboots per day, that would
>> take rather a long time: a little under 500 years if my arithmetic
>> is working.
>
> I think you're confused.  23 means a check each 23 mounts.  With 2
> mounts per day, that's a check every 12 days for the first and second
> disk.

I think the point is that 23, 24, 25, 26 are relatively prime so that,
if N is initially zero, it takes 23x24x25x26 increments initially for (N
mod 23), ..., (N mod 26) to all again be zero.

> Also, except mount count, there's also a time-based check.  The check
> happens whichever of the two expires first (otherwise, a system that
> gets rebooted once each two months or such would get checked in a
> timely manner.)

This second point is quite valid.

allan