SLUG Mailing List Archives
[SLUG] I hate udev!
- To: slug@xxxxxxxxxxx
- Subject: [SLUG] I hate udev!
- From: Peter Rundle <prundle@xxxxxxxxxxxxxx>
- Date: Wed, 23 Nov 2005 13:54:14 +1100
- User-agent: Mozilla Thunderbird 1.0.6-1.1.fc4 (X11/20050720)
<rant emotion="annoyed" sanity="atrisk">
Yes I hate udev because if my server is rebooted and the tape drive
isn't switched on then the entries in /dev/ such as nst0 don't get
created. Then my backup fails or worse the disk is completely full
because writing to /dev/nst0 when the device file doesn't exist creates
a data file on the disk which grows to be bigger than the /dev
partition. I don't want to reboot my server right now but I'd love to be
able to do a backup. Is there a sane way to tell udev to create the
entries for the device without rebooting?
In the "bad old days" when I was using System V you simply created the
device file with mknod and that was it. Of course you had to know the
major and minor numbers but that could be determined by the scsi address
and once that was sorted it was straight forward.
Now in Linux figuring out what a device file's name and major and minor
numbers should be appears to be some sort of sadistic guessing game
devised by some manic kernel developer.
E.G. On SystemV
Scsi: Channel 1, ID 2, partition 5 ==> /dev/rdsk/c1d2s5
But who could tell me what the device name would be on Linux?
Well that'd be a grand guessing game depending on what other devices you
had attached / where turned on at the time you last rebooted the system.
(which manic devised this concept? Linus? yeah thought so, he is crazy!)
Assuming I can find out what the major and minor numbers should be can I
just use mknod to make the device permanent or will udev overwrite /
delete it again?
Can I get rid of udev? Or will my disks evaporate in a puff of lost
Can anyone tell me what, if any, simple steps I can take to get my tape
visible again without rebooting?
(Oh FC4 btw)