Each running virtual machine has its own log file, vmware.log, stored on the VMFS volume. By default, the log file is rotated whenever the virtual machine is powered on, but file rotation is configurable.

■

ESXi maintains six log files that rotate at each power-cycle (the default) or at a configured file size.

■

ESXi can be configured to maintain a specific number of log files. When the limit is reached, the oldest file is deleted.

■

VMware recommends a log file size of 500 KB.

■

Messages that are generated by VMware Tools are logged separately.

Example: VMkernel Availability Report
Availability Report for <servername>
Feb 27, 2008 - May  7, 2008

Availability: 99.949%
     Total time: 69 days, 15 hours
     Uptime: 69 days, 14 hours
     Downtime: 51 minutes

Note: Downtime is any time the system isn't capable of running
Virtual Machines.  This includes reboots, crashes, configuration and running linux

Downtime Analysis:
     0.1% (51 minutes) downtime caused by:
     13.1% (6 minutes) scheduled downtime
     86.9% (44 minutes) unscheduled downtime

Reasons for scheduled downtime:
     84.9% server rebooting (1 instance)
     9.4% VMkernel unloaded (1 instance)
     5.7% server booting (3 instances)

Reasons for unscheduled downtime:
100.0% unknown (powerfail / reset?) (1 instance)
     
Stats:
     Current uptime: 8 days, 11 hours
     Longest uptime: 61 days, 2 hours
     Shortest uptime: 38 minutes
     Average uptime: 23 days, 4 hours
     Longest downtime: 44 minutes
     Shortest downtime: 7 seconds
     Average downtime: 8 minutes
     Maximum VMs Sampled:  1
     Average VMs Sampled: 0.94

Server Information:   Number of CPUs:  4 logical 4 cores
      2 packages,  Intel(R) Xeon(R) CPU            5150  @ 2.66GHz
        Installed Memory:     2096416 kB
        Current Build:  78591
Report generated Wed May  7 04:02:04 PDT 2008