Bert Zefat's Tech Blog

There are some Advanced Settings that you can change from within your VMware HA Cluster.

das.AllowNetwork
By default the Service Console portgroup is used for failure detection. By entering in das.AllowNetwork you can specify an additional portgroup to use.

das.isolationAddress
By default VMware HA nodes check heartbeats of other nodes . When this heartbeat is lost the suspected Isolated nodes then pings its Service Console gateway by default to check that it is truly isolated. By using the das.isolationAddress command, you can add additional IP addresses for the server to check. These IPs must be on the Service Console portgroup, or in the portgroup you’ve added for das.AllowNetwork

das.failureDetectionTime
This is the time required before VMware HA considers a host to be Isolated.Default setting is 14 seconds, this can be changed to a setting that will better fit your needs.

das.failureDetectionInterval
This is the rate of monitoring between VMware HA nodes, think of this as a heartbeat check.
Default setting is 1 second, if you feel that this is just too often you can change it.

Tags: ESX, VMware by Bert Zefat
No Comments »

Be alerted on a default setting on ESX 4, which is potentially dangerous these days.

If you hit Ctrl-Alt-Del on an ESX 4 console, it will reboot the server even if there are running VMs and it doesn’t care if the server is not in Maintenance Mode. Even if your not logged on it will capture the Ctrl-Alt-Del and reboot.

This is an old throwback which most modern Linux distribution disable these days.

To disable this yourself, open up /etc/inittab in your favourite editor and comment out the “ca::ctrlaltdel:/sbin/shutdown -t3 -r now” line with a # symbol so it looks like this:

# Trap CTRL-ALT-DELETE
# ca::ctrlaltdel:/sbin/shutdown -t3 -r now

Save and exit the file. For this to take effect without a reboot, then run: init q This certainly disabled by default on ESX 3.5 hosts, so I assume that this was an oversight on VMware’s part on the new release.

Tags: ESX, VMware by Bert Zefat
No Comments »