There are two log files stored on the host system to assist with debugging Xen related problems. The file /var/log/xen/xend.log holds the same information reported with 'xm log. Unfortunately these log messages are often very short and contain little useful information. The following is the output of trying to create a domain running the kernel for NetBSD/xen.
[2005-06-27 02:23:02 xend] ERROR (SrvBase:163) op=create: Error creating domain:(0, 'Error')
Traceback (most recent call last):
File "/usr/lib/python2.4/site-packages/xen/xend/server/SrvBase.py", line 107, in _perform
val = op_method(op, req)
File "/usr/lib/python2.4/site-packages/xen/xend/server/SrvDomainDir.py", line 71, in op_create
raise XendError("Error creating domain: " + str(ex))
XendError: Error creating domain: (0, 'Error')
The second file, /var/log/xen/xend-debug.log usually contains much more detailed information. Trying to start the NetBSD/xen kernel will result in the following log output:
ERROR: Will only load images built for Xen v3.0
ERROR: Actually saw: 'GUEST_OS=netbsd,GUEST_VER=2.0,XEN_VER=2.0,LOADER=generic,BSD_SYMTAB'
ERROR: Error constructing guest OS
When reporting errors, always include the output from both /var/log/xen/xend.log and /var/log/xen/xend-debug.log.
If starting a fully-virtualized domains (ie to run unmodified OS) there are also logs in /var/log/xen/qemu-dm*.log which can contain useful information.
Finally, hypervisor logs can be seen by running the command