Subject: Re: /etc/rc.d/ runs slowsly
To: NetBSD-current Discussion List <email@example.com>
From: Robert Elz <kre@munnari.OZ.AU>
Date: 04/12/2000 09:05:34
Date: Mon, 10 Apr 2000 23:27:22 -0400 (EDT)
From: firstname.lastname@example.org (Greg A. Woods)
| Did you not know that /usr was split off only because the disks were too
| small to keep everything on one way back in the early days
That's how I heard it too - but this split must have occurred way back
very early in the days before anyone outside Bell Labs had ever heard of
unix (as I remember it, even the CACM paper had /usr in it).
In any case, that the original reason something was done is no longer
relevant doesn't mean that there is no longer any reason for it...
I prefer to keep / small (and as stable as possible too) not because I
can't find a drive big enough to hold both it and /usr, but because I
prefer to replicate it widely (on every drive I can boot from, at least
until I have more copies than I can manage). For that, on systems I
really care about, I have / mirrored, so there is always an up to date
copy of it on another drive (on another controller), and then I also
have a couple of increasingly less frequently updated copies, so I always
have a root that was known to be workable, sometime in the past (mirrors
don't help when someone installs a broken init, or does rm -rf /).
For this to succeed, the space used needs to be small - again, not because
the cost ($ terms) would be too huge to keep four or five copies around,
but because when someone sees most of the filesystems full, and they need
some extra space to do some work in a hurry, a 200-500 MB (whatever it takes)
space that isn't mounted, and doesn't look to being actively used for
anything is a very tempting target. A 25Mb partition (which is what I
like / to be) isn't usually very interesting or useful - it is usually
possible to recover that much by just finding a few core files and nuking
them (or some .o's or netscape caches, or ...)
For backup of /usr a CD is a wonderful choice - nothing on /usr needs to
be writeable in ordinary use (only for installing new versions), CD blanks
are real cheap, and they aren't susceptible to be overwritten by something
more immediately useful... Putting / on a CD is a much less useful choice,
unwriteable root partitions (while useful for minimal tasks) are much harder
to deal with.
In any case, you're free to keep combining /usr and / in one partition if
that suits you, as is anyone else - but I suspect that we've all become
rather tired of hearing that it is the way things ought to be done.