Ben Stanley wrote:
So SCSI is not electrically designed for hot-plugging, and most pieces
of SCSI equipment come with dire warnings against doing so...
Agreed. However, I don't believe for a minute that all devices connected
to a scsi chain have to be on for the chain to be valid. It's quite
acceptable to turn a device connected to the chain off. Removing the
terminator / breaking the chain however, is a definite no no.
[snip]
When you run the modprobe, it scans the SCSI bus, and all the hotplug
stuff fires off and causes udev to create the necessary nodes in /dev .
So, your problems are not udev's fault, they are the fault of the
original SCSI specification, which it sounds like you have outgrown.
Bollocks. In my opinion, the fault is that the udev design doesn't
consider a situation where a device is plugged into the scsi bus but not
turned on at boot time. When the server rebooted the tape was turned
off. Why is recovering that situation such a big deal for Linux?
That I should have to fix such a simple situation by "knowing my system
(i.e the inner workings of udev) better" loading modules or reading
through kernel header files is a bollocks attitude. Udevd should either
just scan the bus periodically (once a minute would be enough) or
provide a tool for me to force a scan and go, "oooh new device on the
scsi bus, better add the device files". If udev can only be triggered to
do that by loading a kernel module then that's a piss poor design. What
if two devices share the same module?
Ok so as a Linux Geek administrator "I'm not worthy" fine I'm over it, I
care nought for learning the latest incarnation of the Unix/Linux
file/device system. I dealt with that years ago, I thought we were
making a OS that was smarter than that, I thought that udevs design goal
was that we'd no longer have to worry about the inner details of device
file names because udev "automagically" takes care of it.
P.
P.S I gave in an rebooted the server during the night. I've now recored
the major and minor numbers of the device file so that if it happens
again I'll just mknod them.
P.P.S thanks everyone for the advice pertaining to backups. Some food
for thought there.
--
SLUG - Sydney Linux User's Group Mailing List - http://slug.org.au/
Subscription info and FAQs: http://slug.org.au/faq/mailinglists.html
