Re: disklabel differences FreeBSD, DragonFly

On Thu, Jul 27, 2006 at 02:28:18PM -0400, Mike Meyer wrote:
In <20060727180412.GB48057@xxxxxxxxxxxxxxxxxxxxxxx>, Rick C. Petty <rick-freebsd@xxxxxxxxxxxxxxxxx> typed:
On Thu, Jul 27, 2006 at 09:49:48AM -0400, Steve Ames wrote:
On Thu, Jul 27, 2006 at 02:21:59PM +0200, Joerg Sonnenberger wrote:
DragonFly disklabels allow 16 entries by default, FreeBSD still limits
it to 8. That's why you can't read it directly.
Are there plans to bump the default up from 8? I'm honestly torn on
this topic whenever I install a new system. On the one hand I like
having a lot of discrete mountpoints to control potential usage. On
the other hand with drive space being so inexpensive I sometimes
wonder if I need to bother and can get away with very few mountpoints.
I would think that cheap disk space would mean larger disks which implies
more mountpoints ???

Nope. One of the historical uses of partitions was to act as firewalls
between subsystems, so that subsystem A running out of space didn't
cause subsystem B to die for lack of space. This had the downside of
making it more likely that one of the two would run out of space
because the excess space from another subsystem could only be used by
it. With cheap disk space, you overallocate by enough to give you
plenty of warning before you have to deal with the issue. You can
safely share that space, and doing so means you have to "deal with the
issue" less often.

These days, the only technical reason I know of for having separate
mountpoints is because you want to run commands that work on
filesystems on the two parts with different arguments or under
different conditions.

Well I still prefer to "design" my filesystems no matter how big
disks are.

So I have better control of what needs backup using dump
and when I need to restore parts of my disk its also quicker
and more reliable to restore a subtree.

Also I'd gues that its still valid that less file movement
in root filesystem increases robustness if you have a power outage.
Same true for other important filesystems.

Also it makes it easier to upgrade a system, since you only nail
/ and /usr, if the rest is in other filesystems.

Also its easier to newfs "/" and "/usr", if "/var", "/usr/local"
and "/usr/X11R6", "/home", ... are on differnet filesystems.

Also you can increase system performance by choosing bigger block and
frag size in filesystems with bigger files on average.

If you have a news filesystem you perhaps want to finetune settings
of filesystem to have more inodes available ...

You see, I think there is still demand for using many filesystems
if you are open minded for having the best support in every "shitty"
situation ;-)


Andreas ///

--
Andreas Klemm - Powered by FreeBSD 6
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