Environment
Novell SUSE Linux Enterprise
Server 10
Situation
When loading many LUNs from
a SAN from the initial ramdisk (i.e. as configured through anINITRD_MODULESsetting in /etc/sysconfig/kernel
which includes HBA drivers) scanning may take a long time. This is
due to the involvement of the VESA Framebuffer.
On some systems
this may even introduce a buffer overflow condition that
will hang the system altogether. This lockup is exhibited on x86_64
installations.
Resolution
There are three primary
solutions:
- Boot the kernel with the parameter vga=normal. E.g., when the
default bootloader, GRUB, is used:
- Edit /boot/grub/menu.lst
- Change 'vga=XXX' to 'vga=normal'.
- Use a serial console instead of the framebuffer console. For details, refer to the product documentation or to KB 3456486: Configuring a Remote Serial Console for SLES.
- Change the kernel 'loglevel' parameter to decrease the verbosity of logging. For example, setting 'loglevel=4' will likely solve the problem. See the "additional notes" section for details.
Additional Information
The loglevel kernel parameter sets the verbosity of the kernel
logging. The default loglevel is 7.
From /usr/src/linux/Documentation/kernel-parameters.txt
loglevel= All Kernel Messages with a loglevel smaller than the
console loglevel will be printed to the console. It can
also be changed with klogd or other programs. The
loglevels are defined as follows:
0 (KERN_EMERG) system is unusable
1 (KERN_ALERT) action must be taken immediately
2 (KERN_CRIT) critical conditions
3 (KERN_ERR) error conditions
4 (KERN_WARNING) warning conditions
5 (KERN_NOTICE) normal but significant condition
6 (KERN_INFO) informational
7 (KERN_DEBUG) debug-level messages