Specifications

Alternative Methods for I/O Fencing
from partially hung servers. In cases where a hung server goes undetected by LifeKeeper, watchdog
will begin recovery. Also, in the case where a server is hung and not able to detect that the
reservation has been stolen, watchdog can reboot the server to begin its recovery.
Alternative Methods for I/O Fencing
In addition to resource fencing using SCSI reservations, LifeKeeper for Linux also supports disabling
reservations. Regardless of whether reservations are enabled or disabled, there are two issues to be
aware of:
l Access to the storage must be controlled by LifeKeeper.
l Great care must be taken to ensure that the storage is not accessed unintentionally such as by
mounting file systems manually, fsck manually, etc.
If these two rules are followed and reservations are enabled, LifeKeeper will prevent most errors from
occurring. With reservations disabled (alone), there is no protection. Therefore, other options must be
explored in order to provide this protection. The following sections discuss these different fencing
options and alternatives that help LifeKeeper provide a reliable configuration even without
reservations.
STONITH
STONITH (Shoot The Other Node in the Head) is a fencing technique for remotely powering down a
node in a cluster. LifeKeeper can provide STONITH capabilities by using external power switch
controls, IPMI-enabled motherboard controls and hypervisor-provided power capabilities to power off
the other nodes in a cluster.
Using IPMI with STONITH
IPMI (Intelligent Platform Management Interface) defines a set of common interfaces to a computer
system which can be used to monitor system health and manage the system. Used with STONITH,
it allows the cluster software to instruct the switch via a serial or network connection to power off or
reboot a cluster node that appears to have died thus ensuring that the unhealthy node cannot access
or corrupt any shared data.
Package Requirements
l IPMI tools package (e.g. ipmitool-1.8.11-6.el6.x86_64.rpm)
STONITH in VMware vSphere Environments
vCLI (vSphere Command-Line Interface) is a command-line interface supported by VMware for
managing your virtual infrastructure including the ESXi hosts and virtual machines. You can choose
the vCLI commandbest suited for your needs and apply it for your LifeKeeper STONITH usage
between VMware virtual machines.
SteelEye Protection Suite for Linux115