Disabling atime

[Les Mikesell]

Dr. Diesel wrote:
> On 8/9/07, Rahul Sundaram <sundaram at fedoraproject.org> wrote:
>> Hi
>>
>> http://kerneltrap.org/node/14148
>>
>> Looks like we get a good performance boost and only tmpwatch and mutt
>> with mbox seems to be affected. A simple patch to tmpwatch has been
>> posted on the same thread.
>>
>> Thoughts on disabling it?
>>
>> Rahul
> 
> I have often thought an entire release (or every ~3-4) should consist
> of nothing but bug fixes and code optimization.  Even at Ingo's 2.3%
> it is worth a healthy discussion, which has already happened!  If much
> faster machines could see 5-10% that would be a major improvement IMO.
> 
> I say lets try it!  How hard would it be to test?  ext3 is the biggest
> issue, but there is a work-a-round?

I'm not sure anyone has mentioned what are probably the biggest uses of 
atime:
   (1) a debugging step to see if a file is actually being read by some 
process.  For example you edit some config file, start the service and 
the change you expect didn't happen.  If atime didn't change, the file 
wasn't read, perhaps due to some other directive passed earlier. 
Likewise with executables that you think should be run, or libraries 
that should be used.
   (2) as an indication that files have never been used and can probably 
be deleted.   Since most backup operations act as a read, this tends to 
not be very useful.

Personally I'd trade these for better performance but I wouldn't want 
the change to be a surprise.

-- 
   Les Mikesell
    lesmikesell at gmail.com