How to do a kernel dump?

[Olivier Nicole]

Hi,

I'd like to get a kernel dump when the machine panics.

I set-up dumpdev="/dev/rda0s1b" in /etc/rc.conf.

My swap is:

amanda<on>41: swapinfo
Device          1K-blocks     Used    Avail Capacity  Type
/dev/rda0s1b      1048448        0  1048448     0%    Interleaved

My memory is only 256 MB, so the swap is large enough to keep up to 4
dumps. But still no dump, no image created in /var/crash, the system
reboots in multi-user mode and period.

When I try savecore by hand I get:

savecore: reboot after panic: page fault
savecore: system went down at Thu Mar  2 01:13:26 2006
savecore: no dump, not enough free space on device (235544 available, need 264924)

How should I understand that? Is it because I use the raw device (that
is not clear in the handbook).

System is:

FreeBSD amanda.cs.ait.ac.th 4.11-RELEASE-p14 FreeBSD 4.11-RELEASE-p14 #5: Tue Feb 28 16:07:07 ICT 2006     root at amanda.cs.ait.ac.th:/usr/obj/usr/src/sys/SMALL  i386

Thanks in advance,

Olivier