Re: autodefrag by default, was: Lots of harddrive chatter

[George Mitchell <george@chinilu.com>]

On 07/21/2013 08:37 PM, Shridhar Daithankar wrote:
> On Sunday, July 21, 2013 04:44:09 PM George Mitchell wrote:
>> Unless auto-defrag can work around the
>> in-use file issue, that could be a problem since some heavily used
>> system files are open virtually all the time the system is up and
>> running.  Has this issue been investigated and if so are there any
>> system files that don't get defragmented that matter?  Or is this a
>> non-issue in that any constantly in use system files don't really matter
>> anyway?  That is really the only question I have before moving away from
>> my current offline approach to the auto-defrag mount option for system
>> filesystems (/, /boot, /usr, /opt, /var, etc).
> AFAIK, defragmentation is proportional to amount of writes to a file or
> direcotries.
>
> system files typically are installed once and never rewritten in place, so
> they should not be much fragmented to begin with.
>
> now their directory objects, is a different story and so is things like
> systemd journal, log files, or database files.
Never rewritten in place?  I wouldn't go that far.  In the case of many 
distros there is a continual flow of updates which results in some 
degree of data churning throughout the system filesystems. Just a kernel 
update, for example, can affect a rather large number of files and 
directories with new writes while application updates (KDE or even Gnome 
for example) can cause a large number of files to be rewritten in place.