On Mon, 13 Nov 2000, Jerry Feldman wrote:
> boot into single user mode. Most linux systems:
> LILO: linux S
> Once in single user mode, you may need to enter your root password.
> Your root file system is mounted read/only.
NOTE WELL: Red Hat and most of its derivatives mount all available
filesystems WRITE ENABLED during a single user boot. Running fsck on a
mounted, writable filesystem can cause SEVERE FILESYSTEM CORRUPTION and LOST
DATA.
Here are the details:
The boot script, /etc/rc.d/rc.sysinit, will do an fsck on any filesystems it
thinks need it. If anything nasty is found ("UNEXPECTED INCONSISTENCY; RUN
fsck MANUALLY"), it will drop you to a root shell with the filesystems still
mounted read-only (if at all). At that point, you can safely run fsck until
it says everything is peachy, at which point you exit the shell, and the
system reboots.
HOWEVER, if the built-in fsck completes successfully, and moves on, it will
mount the filesystems read/write before dropping you to the single user mode
shell prompt. Running fsck at this time could DESTROY the filesystem.
If you want to force the system to boot with a read-only filesystem,
override the initial program with something like:
LILO: linux init=/bin/sh
That will cause the kernel to load bash as the one and only process on the
system. You can then mount the /proc filesystem with:
mount -t proc /proc /proc
Then inspect the contents of /proc/mounts to verify root (/) is mounted
read-only. Then run fsck or whatever. Then sync. Then issue:
exec /sbin/init
That will replace the current shell with init, and the system should start
normally.
--
Ben Scott <[EMAIL PROTECTED]>
Net Technologies, Inc. <http://www.ntisys.com>
Voice: (800)905-3049 x18 Fax: (978)499-7839
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