From: George Vieira [mailto:[EMAIL PROTECTED]]
>I was just wondering why is it so crucial to have different
>mount points on
>a unix system? Eg. create /, /usr , /tmp , /home
>
>Why is it so much better to have multiple partitions instead of having
>everything mounted as (/) root?
>Sure some times the file system could crash and at least it's
>only 1 file
>system and root or /home or /usr is still OK but what other reasons are
>there? Speed? Fragmentation? Etc.....
Not that important on a single machine because quotas and the like can
prevent most users from filling the partitions, but on a larger
installation:
1. You usually want /usr and /home to be the same no matter what machine you
log in from (well, /usr should be the same for clients of the same
architecture). This makes them NFS mount points, or local partitions if you
are on the server itself.
2. You quite possibly want to mount /usr as read only for normal users.
Sort of a belt and bracers approach to security - don't just trust
permissions, mount the damn partition as read only as well.
3. Having a small root partition means you can recover it quickly. In fact,
having a stock standard root partition means you can install new machines in
lightning quick time and just have everything else as NFS mounts (except
/tmp of course).
4. /tmp can (and will) fill up. Same for /var.
5. You may want to have things like /home on a journalled file system (for
fault tolerance) and /tmp on a fast, simple file system. Large systems even
have /tmp on a ramdisk. Starting with different partitions gives you this
flexibility.
6. Quotas can be manages more simply by just setting one quota for a user on
each partition (in fact, on Linux this is the only way you can do it). You
may allow a user 1G in their /home folder but only a few meg in /tmp or
/var.
7. If /root gets trashed you can access /var, /home and other critical
pieces of information.
8. When you upgrade your drive space you just have to move the partitions
one at a time. For example you may move /home to a new RAID array and
expand /var to where /home was.
I'm sure there are other reasons...
John Wiltshire
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