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Managing Solaris system crash
Why I want to do this
Because when a system crashes you want to have saved crash dump file in order to troubleshoot an issue.
What can happen - see below:
- Hardware, I/O and software problem can cause system to crash
- System crashes and display errors on the console
- Copy of physical memory is written to the dump device
- The system reboots automatically
- When system reboots, command savecore runs and retreive data from dump device
- Note 1: You can get crash dump of live running system with command: savecore -L
- Note 2: This will require dedicated dump device , you cannot use swap
- The saved crash dump is written to 'savecore' directory
- Written files are unix.X and vmcore.X and X is dump sequence number
- Be careful - don't confuse crash dump files with 'core' files which occures when application terminates abnormally.
- By default, crah dump files are saved in /var/crash/hostname directory (can be changed, see later ...)
How to manage system crash dump
Use the command dumpadm to configure (make sure service svc:/system/dumpadm:default is enabled):
Note: I've been seeing people use swap as dump device.
In such setup, the swap is under control of SVM and this is recommended.
But in this case, Sun documentation advises to keep dump device separate.
- dump content
- dump device
- This stores dump data temporarilly as system crashes.
If it is not swap, savecore runs in the background, which speeds up boot process.
- directory where crash dump files are saved
Syntax - see man page for details
dumpadm -c content -d dump_device -m min_free_disk_space -n -s savecore_dir
-c = kernel | all |curproc
-d = must be block device, like /dev/dsk/c1t0d0s4
-m = something like 100m
-n = don't run 'savecore' when system reboots
-s = specify alternate dir for storing crash dump file, the default is /var/crash/hostname
What now after having crash dump ?
I guess you'll send to support provider, or you can examine yourself using 'mdb' tool, something like:
mdb -k unix.0
... see some output (note: 2 x : before status)
... see some output
exit with Ctrl+D
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