Forcing a crash dump and rebooting the system is sometimes necessary for troubleshooting purposes. The savecore feature is enabled by default.
For more information on system crash dumps, see Chapter 17, Managing System Crash Information (Tasks), in System Administration Guide: Advanced Administration.
If you cannot use the reboot -d or the halt -d command, you can use the kernel debugger, kmdb, to force a crash dump. The kernel debugger must have been loaded, either at boot, or with the mdb -k command, for the following procedure to work.
You must be in text mode to enter the kernel debugger (kmdb). So, first exit any window system.
If a locally-attached keyboard is being used as the system console, press F1-A on that keyboard. If the system is configured to use a remote (serial) console, use the mechanism that is appropriate to that console to send a break character.
The kmdb prompt is displayed.
Use the systemdump macro to induce a crash.
Panic messages are displayed, the crash dump is saved, and the system reboots.
Verify that the system has rebooted by logging in at the console login prompt.
This example shows how to force a crash dump and reboot of the x86 based system neptune by using the halt -d and boot commands. Use this method to force a crash dump of the system. You will need to manually reboot the system after running the halt command with the -d option.
# halt -d Aug 11 12:51:27 neptune halt: halted by <user> panic[cpu45]/thread=d3971a00: forced crash dump initiated at user request d363ae58 genunix:kadmin+bd (5, 0, 0, d3fefac0) d363af88 genunix:uadmin+88 (5, 0, 0, 0, 0, d363afb4) syncing file systems... done dumping to /dev/dsk/c0t0d0s1, offset 107806720, content: kernel 100% done: 40223 pages dumped, compression ratio 4.11, dump succeeded Press any key to reboot. Resetting... . . . SunOS Secondary Boot version 3.00 Autobooting from bootpath: /pci@0,0/pci1028,10a@3/sd@0,0:a Running Configuration Assistant... If the system hardware has changed, or to boot from a different device, interrupt the autoboot process by pressing ESC. Initializing system Please wait... <<< Current Boot Parameters >>> Boot path: /pci@0,0/pci1028,10a@3/sd@0,0:a Boot args: Type b [file-name] [boot-flags] <ENTER> to boot with options or i <ENTER> to enter boot interpreter or <ENTER> to boot with defaults <<< timeout in 5 seconds >>> Select (b)oot or (i)nterpreter: Loading kmdb... SunOS Release 5.10 Version s10_62 32-bit Copyright 1983-2004 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. configuring IPv4 interfaces: iprb0. add net default: gateway 172.20.26.248 Hostname: neptune The system is coming up. Please wait. checking ufs filesystems /dev/rdsk/c0t0d0s7: is logging. NIS domain name is example.com starting rpc services: rpcbind keyserv ypbind done. Setting netmask of iprb0 to 255.255.255.0 Setting default IPv4 interface for multicast: add net 224.0/4: gateway venus syslog service starting. System dump time: Wed Aug 11 12:51:29 2004 Aug 11 13:13:26 venus savecore: saving system crash dump in /var/crash/venus/*.1 Constructing namelist /var/crash/venus/unix.1 Constructing corefile /var/crash/venus/vmcore.1 100% done: 42157 of 42157 pages saved volume management starting. The system is ready. . . .