Subject: Re: Why root and usr in separate partitions?
To: Scott Horton <>
From: Justin Heath <>
List: netbsd-users
Date: 06/29/2001 18:01:28
--- Scott Horton <> wrote:
> This is just a generalized *nix question, really.
> I'm not new to *nix, but I've never spent the
> requisite time to become
> knowledgeable about it.  Generally, I've just done
> enough to solve a
> problem, then went back to other things.
> I *have* however, been at it for a while (TRS-80
> Model 16 Xenix running on
> was probably my first exposure) - and I've noticed
> that there's a
> longstanding tradition of breaking up a perfectly
> nice single hard drive
> into lots of little partitions for different
> sections of the file system,
> such as root, /usr, /home, and so forth.  I've
> always wondered about this -
> it seems kind of wasteful, especially in an OS that
> allows you to define
> your own block and cluster sizes (unlike FAT16,
> FAT32, etc).  I do
> understand that SWAP is normally a separate
> partition, because it's not
> (usually) a traditional filesystem.
> So - my question - in a single-disk system, why this
> longstanding tradition
> of breaking the filesystem up into multiple
> partitions?  (There!  I've
> unveiled my ignorance of *nix filesystems in
> general!)
> Scott
> Scott Horton
> 111 E. Forest Ave
> Columbia, MO 65203

According to me:

1. Security, enforcing limitations can be useful to
limit diskspace and prevent a local DOS attack by
filling up the disk. Also it is a good practice to
mount any filesystems you can read only before
installing software. This can limit the effect of a
trojan or malicious program.

2. Performance, putting a filesystem that has a large
amount of disk I/O on a faster part of the disk can
greatly improve performance.

3. Recovery, as pointed out by Manuel Bouyer having a
small partition for root towards the inside of the
disk may help prevent damage. Also it is good practice
to set up partition sizes according to the size of
your backup media. This can speed up disaster recovery
a lot.

I know there are more benefits that I am forgetting
but hopefully someone else can point these out.

And BTW as you can tell I am a fan of many partitions
thanks to those who helped in upping the limit to 16!

--Justin Heath

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