/var/log/vmksummary.logcontains information regarding ESXi host startup and shutdown, and an hourly heartbeat with uptime and other metrics.
The vmksummary log contains bootstop messages indicating startup and shutdown of the ESXi host. For example:
yyyy-mm-ddThh:mm:ssZ bootstop: Host has booted
yyyy-mm-ddThh:mm:ssZ bootstop: Host is rebooting
yyyy-mm-ddThh:mm:ssZ bootstop: Host is powering off
yyyy-mm-ddThh:mm:ssZ bootstop: Host is halting
Every hour, a heartbeat message is written to the vmksummary log. This information can be useful to indicate the liveliness of the ESXi host and its logging, or to review virtual machine quantities or component memory usage over time.
yyyy-mm-ddThh:mm:ssZ heartbeat: up UPTIME, NNN VMs; [memory leaderboards]
Memory usage leader boards show the three userworld processes on ESXi which have the highest resident, non-swapped memory usage:
[PID ProcessName nnnkB]
[PID ProcessName nnn%max]
2011-08-30T04:00:01Z heartbeat: up 0d17h24m17s, 0 VMs; [[3411 sfcb-pycim 12516kB] [3041 vpxa-worker 12668kB] [2723 hostd-worker 33844kB]] [[3348 sfcb-vmware_int 2%max] [3423 sfcb-vmware_bas 5%max] [3411 sfcb-pycim 16%max]]
During ESXi host startup following a purple diagnostic screen, the host checks for new contents in the configured Diagnostic Partition on disk. For more information, see Collecting diagnostic information from an ESX or ESXi host that experiences a purple diagnostic screen (1004128) and Configuring an ESX/ESXi host to capture a VMkernel coredump from a purple diagnostic screen (1000328).
yyyy-mm-ddThh:mm:ssZ bootstop: Core dump found