SYSRUTH@UTORPHYS.BITNET (Ruth Milner) (01/07/89)
In v7n77, Our Moderator writes:
[[ If /usr is on its own partition, you don't even have to mess with the
"mini-root", just boot single user. In order to do this, however, you
need to have made a dump of your /usr partition in the recent past. But
you should be doing that periodically anyway. --wnl ]]
This is fine for 3.X systems. However, under 4.0, *all* executable images
which used to be in /etc now are just symlinks to the corresponding
programs in /usr/etc. This includes such vital commands as ifconfig,
newfs, mkfs, dump, and - charmingly - restore. When the system boots
single-user, both / and /usr are pre-mounted and available. So if your 4.0
/usr is trashed, unless you have put copies of those images in /etc to
replace the links, you have no choice but to boot the mini-root to restore
your /usr dump(s). And even then, you have to watch out for programs which
call other programs (e.g. newfs runs mkfs).
This has got to be the thing I dislike most about 4.0. In order for your
system to boot, it is now totally dependent on two partitions instead of
one, so there are two crucial points of filesystem failure (three if you
count swap). Yuck.
Ruth Milner
Systems Manager
University of Toronto Physics
sysruth@helios.physics.utoronto.catrinkle@purdue.edu (01/14/89)
In v7n92 Ruth Milner writes: > This is fine for 3.X systems. However, under 4.0, *all* executable images > which used to be in /etc now are just symlinks to the corresponding > programs in /usr/etc.... There is a directory called /sbin that really is in the root file system. It contains hostname, ifconfig, init, mount, and sh. If you wish you can copy fsck, mkfs, and restore into /sbin as well. Daniel Trinkle trinkle@cs.purdue.edu Dept. of Computer Sciences {backbone}!purdue!trinkle Purdue University 317-494-7844 West Lafayette, IN 47907
escott@uunet.uu.net (E. Scott Menter) (01/14/89)
> This has got to be the thing I dislike most about 4.0. In order for your > system to boot, it is now totally dependent on two partitions instead of > one, so there are two crucial points of filesystem failure (three if you > count swap). Yuck. Well, this has been said before, but the point is that /usr should be mounted read-only under 4.x. As a result, you should more or less never have a trashed /usr partition. And, I find it a nice thing to have under single user (never did like editing system files with "ed" 8^). Scott Menter Sr. Network Administrator Shearson Lehman Hutton escott@shearson.com uucp!slcpi!escott
escott@uunet.uu.net (E. Scott Menter) (01/24/89)
> what's the argument that says /usr should be r/o on the server?
Just that, that it's nice not to have to worry about it. Even so, if it's
mounted rw on the server but ro on the clients, the chance for corruption
is quite small. And most of what you need is in /sbin anyway, or at least
in miniroot 8^).
Scott Menter
Shearson Lehman Hutton
escott@shearson.com