How can I create more sd device files in SLES 9?

tlemons · 01-10-2007, 12:13 PM

My SLES 9 SP3 system has 4096 /dev/sd* files: 256 'major' files each with 16 'minior files. I need to create more sd files, so that my system can handle more than 256 disks. I thought that Linux 2.6 kernel systems were supposed to just do this automatically, but this isn't happening.

Is there a knob I need to turn somewhere?

Thanks!
tl

kilgoretrout · 01-10-2007, 01:58 PM

The 2.4 kernel had a limitation on the device major numbers allowed(1-255) but I thought that limit no longer existed in the 2.6 kernels. Normally you would create a device file with the mknod command(see man mknod) which, for block devices, would have the syntax:

# mknod <device name> -b Major Minor

Have you tried creating a device file with mknod? If it refuses to go ,it could be a kernel limitation.

tlemons · 01-10-2007, 02:02 PM

Thanks for the reply. Yes, mknod works just fine. But I want to fix the problem the 'right way', and understand why SLES 9 didn't just create more sd files automagically. Any ideas?

Thanks!
tl

kilgoretrout · 01-10-2007, 03:18 PM

You would have to carefully parse through all your init scripts to find that and then properly edit them to get the desired number of device files. The init scripts never anticipated anyone would need more that 256 drives and are set up that way by default. I'd just run the necessary mknod commands out of rc.local so you get your extra device files on every boot without potentially screwing up your init scripts.

tlemons · 01-16-2007, 03:17 PM

Here's the solution to my problem. In SLES 9 SP3, chkconfig boot.udev is off by default. This means that udevstart is not run by default, and so will not create additional /dev/sd* files if needed. So, when I ran udevstart, poof!, all the additional /dev/sd entries were created. And, using 'chkcondig boot.udev on' will allow this to happen automatically.

FYI, 'chkconfig boot.udev' is on by default in SLES 10.

tl