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Re: wasted disk space

On Sat, Sep 30, 2000 at 06:34:07PM +0200, Bernd Eckenfels wrote:
> On Sat, Sep 30, 2000 at 05:35:48PM +0200, Massimo Dal Zotto wrote:
> > I found that of my 2GB root filesystem more than 10% is wasted because it has
> > been formatted by the potato installer with a 4K block size instead of 1K.
> What exactly is on your /-mountpoint? home? var? usr? opt? Everything?
> Can we have that awk script please and thanks for your work. I guess the
> reason is, that nobody has bothered to change the default of mke2fs. The
> default is actually calcilated from the File System size (and if it is news
> or not). So perhaps we should talk to Ted about that?

What you have here is a case of usage v speed.  Your files are broken up
by the file system in to blocks and scattered over the disk surface. 

To store a file which contains just a single character will take up one block.  
Not very efficient in terms of disk usage.

However a large file which requires many blocks also requires the disk heads
to seek many time toaccess them.  If the block size is small then more head
seeking is required and performance goes down. (There's a lot more to block
positiong than this.)

As a sysadmin it is your job to configure the partion in the best way for
the job it has to handle.  If the disk is storing emails or news then file
size is, on the whole, small and performance not such a big issue.  If the
file system is holding a database then performance (and a bigger block size)
is better.

Don't worry about the wasted 10%.  The missing space is taken up with the
end of files that don't fit into a block.  File systems often fragment
the little bits of the files left over and place them into one block.  The
problem with these fragments is that to get them requires more CPU then
full blocks.

At the end of the day its the old choice of cost against performance.  Your
system; you decide.

                                Steve Dobson steve.dobson@krasnegar.demon.co.uk

If bankers can count, how come they have eight windows and only four tellers?

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