Kernel Security vs UptimeKernel Security vs Uptime
For best system security you want to apply kernel security patches ASAP. For an attacker gaining root access to a machine is often a two step process, the first step[...]
Category: Ha
ISP Redundancy and VirtualisationISP Redundancy and Virtualisation
If you want a reliable network then you need to determine an appropriate level of redundancy. When servers were small and there was no well accepted virtual machine technology there[...]
ECC RAM is more useful than RAIDECC RAM is more useful than RAID
A common myth in the computer industry seems to be that ECC (Error Correcting Code – a Hamming Code [0]) RAM is only a server feature. The difference between a[...]
Controlling a STONITH and Upgrading a ClusterControlling a STONITH and Upgrading a Cluster
One situation that you will occasionally encounter when running a Heartbeat cluster is a need to prevent a STONITH of a node. As documented in my previous post about testing[...]
Starting a Heartbeat Resource Without HeartbeatStarting a Heartbeat Resource Without Heartbeat
The command crm_resource allows you to do basic editing of resources in the Heartbeat configuration database. But sometimes you need to do different things and the tool xmlstarlet is a[...]
Testing STONITHTesting STONITH
One problem that I have had in configuring Heartbeat clusters is in performing a STONITH that originates outside the Heartbeat system. STONITH was designed for the Heartbeat system to know[...]
Xen and HeartbeatXen and Heartbeat
Xen (a system for running multiple virtual Linux machines) and has some obvious benefits for testing Heartbeat (the clustering system) – the cheapest new machine that is on sale in[...]
configuring a Heartbeat serviceconfiguring a Heartbeat service
In my last post about Heartbeat I gave an example of a script to start and stop a cluster service. In that post I omitted to mention that the script[...]
Heartbeat service scriptsHeartbeat service scripts
A service script for Heartbeat needs to support at least three operations, start, stop, and status. The operations will return 0 on success, 7 on failure (which in the case[...]
Another Heartbeat 2.0 STONITH example configurationAnother Heartbeat 2.0 STONITH example configuration
In a Heartbeat cluster installation it may not be possible to have one STONITH device be used to reboot all nodes. To support this it is possible to have multiple[...]