I think there is rarely a valid reason to split a single disk system into
multiple small partitions. In fact, the Multi-Disk HOWTO agrees:
In fact, for single physical drives this scheme offers very little
gains at all, other than making file growth monitoring easier
(using 'df') and physical track positioning. Most importantly
there is no scope for parallel disk access.
Much of this is just Unix tradition from the days when large disks were
slow and small disks were fast, which is why we still have things like
/tmp, /usr/tmp, and /var/tmp -- all slightly different. Modern Linux
machines do not have these problems for the same reason that you no longer
have to turn a big crank on the front of your car to start it.
The one overriding exception is that /boot may need to be on a small
partition so that it the kernel can load it using only BIOS calls. If a
machine without LBA BIOS support has a large drive, then /boot must be
placed into the first 1024 cylinders. Older versions of Lilo may force
this requirement also, as may a need to boot non-Linux operating systems
on the same machine. For Linux, in general, such restrictions are ending.
RAID introduces a particularly good reason to split partitions, especially
to have a separate swap partition if you plan to swap onto RAID. For
example, we have two RAID-1 sets using two 30 GB identical drives:
/dev/md0 /dev/hda1 + /dev/hdc1 29.7 GB RAID-1
/dev/md1 /dev/hda2 + /dev/hdc2 0.3 GB RAID-1
We use /dev/md0 for the root fs and /dev/md1 for swap. Why? Because it
takes about 90 minutes to remirror /dev/md0 and only about 2 minutes to
remirror /dev/md1. Since we cannot turn on swapping onto RAID while a
remirror is in progress, we only have to delay enabling swap for 2 minutes
until /dev/md1 is completed.
-- Mike
On Fri, 31 Mar 2000, Gregory Leblanc wrote:
> Check out the "multi-disk-HOWTO" (the name might be slightly different) by
> Stein Gjoen. You get get it from http://www.linuxdoc.org/. It has a very
> good explanation of how and why things are the way they are. One of the
> best HOWTOs around.
> Greg
>
> > -----Original Message-----
> > From: Glenn Hudson [mailto:[EMAIL PROTECTED]]
> > Sent: Friday, March 31, 2000 1:27 AM
> > To: Linux-RAID
> > Subject: multiple partitions
> >
> >
> > Hi,
> >
> > I am hoping someone might help me understand why Linux is
> > usually setup
> > a certain way.
> >
> > Most Linux PC have only one disk drive yet it is recommended that the
> > disk be partitioned into many pieces (home, root, var, swap).
> > I thought
> > this kind of setup would cause excessive disk head movement.
> > What is the
> > advantage of have root, home, var in seperate partitions and why isn't
> > disk head movement excessive?
> >
