[K12OSN] noatime mount option for better performance

[Les Mikesell]

Michael Blinn wrote:
> Forgive the lateness; I've been on vacation.
> 
> I've used 'defaults,noatime' for my /boot /var and /usr/local/ 
> partitions since I built the server last year. It works well, and from 
> my tests cuts the load significantly.
> 
> I started with /var/ because I do a lot of DB stuff, and that's where 
> MySQL keeps its things by default, as well as log files
> /usr/local/ is where my custom anti-spam and imap servers are
> /boot/ I just threw in there as an afterthought. I'll try /tmp/ next. I 
> definitely can't use /home/ because I have backup scripts that compare 
> file modification timestamps, though I imagine there are a host of other 
> reasons not to.

It's not likely that your backup scripts check atime.  Normally you want 
them to use ctime which will catch any modification of the file or its 
attributes (mtime only catches changes to the file contents).

> I do imagine I'll eventually run into some weird error that is caused by 
> a program looking for a timestamp change, I just haven't found it yet.

There is some discussion on the fedora development list about making 
noatime the default for the distribution - and ubuntu may already do it. 
The only thing anyone has found that it affects is the tmpwatch script 
that cleans unused files from the tmp directory and some feature of mutt 
(a text mode email reader) that has a workaround.  Sometimes atime is 
helpful when debugging (did a process read a certain file before 
crashing?) or when cleaning up old files that you can tell haven't been 
read, but otherwise you don't really need it.

-- 
  Les Mikesell
    les at futuresource.com