Disclaimer: Ensure these changes have been thoroughly tested and confirmed with VMware support prior to rolling out into production. Most of these changes and tips may be undocumented by VMware, test at your own risk!

Map Service Console/COS VMDK to specific ESX host (useful if you boot from SAN):

grep -i "hostname" /vmfs/volumes/[datastore]/[esxconsole-datastore-uuid]/logs/sysboot-vmkernel-late.log
[root@everest ~]# grep -i "hostname" /vmfs/volumes/everest-local-storage/esxconsole-49a095a4-204d-c7ba-9bb8-001f29c7b048/logs/sysboot-vmkernel-late.log
0:00:00:06.289 cpu1:4105)Config: 363: "HostName" = "everest.primp-industries.com", Old value: "localhost" (Status: 0x0)

Retrieve VmId from vmware-cmd similiar to that in vimsh/vmware-vim-cmd (only available on classic ESX, not sure why it's not in vCLI):

vmware-cmd /vmfs/volumes/[datastore]/[path_to_vm]/vm.vmx getid
[root@everest ~]# vmware-cmd /vmfs/volumes/d32c5a97-e039bdbf/vCenter-ESX4.02172009/vCenter-ESX4.02172009.vmx getid
getid() = 32

VMware FT statistics and debugging utility
Available after some patch set, generally 4.0u1+

[root@esx-5 ~]# ft-stats
Usage: ft-stats [-hvf] [-c ] [-l] [-n ] [-d ] [-s ] [-w ]
-h, --help Show this message
-v, --verbose verbose output
-f, --force Continue even if version check fails
-c, --cache Use VSI cache file
-l, --list list FT VMs
-n, --iterations Print stats for n iterations
-d, --delay Print stats every n secs (default:5)
-s, --snapshot Collect stats for n secs
-w, --world Print stats for worldID

Note: This tool is intended to assist in troubleshooting and should only be used
with direction by VMware support. All other use of this tool is unsupported.

esxupdate - Query for installed/retired packages with undocumented "--vib-view" option

esxupdate --vib-view query
[root@himalaya ~]# esxupdate --vib-view query
--------------------------------------VIB ID------------------------------------- Package State -----------Timestamp------------
rpm_vmware-esx-drivers-scsi-fnic_400.1.1.0.109.2vmw-2vmw.1.9.208167@x86_64 installed 2010-01-06T12:24:38.100201-05:00
rpm_acpid_1.0.4-9.el5_4.2@x86_64 installed 2010-04-02T17:09:44.566014+00:00
rpm_samba-client_3.0.33-3.15.el5_4.1@x86_64 installed 2010-04-02T17:09:44.171847+00:00
rpm_nss_3.12.3.99.3-1.2157.vmw@x86_64 installed 2010-04-02T17:09:41.148547+00:00
rpm_initscripts_8.45.19.EL-1.2442.vmw@x86_64 installed 2010-04-02T17:09:36.911452+00:00

Change default COW (copy on write) disk growth value
Query (Default is 16MB):

[root@himalaya ~]# esxcfg-advcfg -g /COW/COWDiskSizeIncrement
Value of COWDiskSizeIncrement is 32768

Set (e.g. 256MB):

[root@himalaya ~]# esxcfg-advcfg -s 524288 /COW/COWDiskSizeIncrement
Value of COWDiskSizeIncrement is 524288

The input value for changing COWDiskSizeIncrement is in sectors

UNIT SECTORS	COW GROWTH SIZE
32768	16MB
65536	32MB
131072	64MB
262144	128MB
524288	256MB
2097152	1024MB
....	....

Easy formula is (SIZE_IN_MB)*(1024)*(2) = SECTOR VALUE