3.5. Configuring ACPI For Use with Integrated Fence Devices
If your cluster uses integrated fence devices, you must configure ACPI (Advanced Configuration and Power Interface) to ensure immediate and complete fencing.
If a cluster node is configured to be fenced by an integrated fence device, disable ACPI Soft-Off for that node. Disabling ACPI Soft-Off allows an integrated fence device to turn off a node immediately and completely rather than attempting a clean shutdown (for example,
shutdown -h now
). Otherwise, if ACPI Soft-Off is enabled, an integrated fence device can take four or more seconds to turn off a node (refer to note that follows). In addition, if ACPI Soft-Off is enabled and a node panics or freezes during shutdown, an integrated fence device may not be able to turn off the node. Under those circumstances, fencing is delayed or unsuccessful. Consequently, when a node is fenced with an integrated fence device and ACPI Soft-Off is enabled, a cluster recovers slowly or requires administrative intervention to recover.
Note
The amount of time required to fence a node depends on the integrated fence device used. Some integrated fence devices perform the equivalent of pressing and holding the power button; therefore, the fence device turns off the node in four to five seconds. Other integrated fence devices perform the equivalent of pressing the power button momentarily, relying on the operating system to turn off the node; therefore, the fence device turns off the node in a time span much longer than four to five seconds.
To disable ACPI Soft-Off, changing the BIOS setting to "instant-off" or an equivalent setting that turns off the node without delay, as described in Section 3.5.1, “Disabling ACPI Soft-Off with the BIOS”. This is the preferred method. Disabling ACPI Soft-Off with the BIOS may not be possible with some systems, however. If disabling ACPI Soft-Off with the BIOS is not satisfactory for your cluster, you can disable ACPI Soft-Off with one of the following alternate methods:
- Use
chkconfig
management and verify that the node turns off immediately when fenced, as described in Section 3.5.2, “Disabling ACPI Soft-Off withchkconfig
Management”. This is the first alternate method. - Appending
acpi=off
to the kernel boot command line of the/boot/grub/grub.conf
file, as described in Section 3.5.3, “Disabling ACPI Completely in thegrub.conf
File”. This is the second alternate method.Important
This method completely disables ACPI; some computers do not boot correctly if ACPI is completely disabled. Use this method only if the other methods are not effective for your cluster.
3.5.1. Disabling ACPI Soft-Off with the BIOS
You can disable ACPI Soft-Off by configuring the BIOS of each cluster node with the following procedure.
Note
The procedure for disabling ACPI Soft-Off with the BIOS may differ among server systems. You should verify this procedure with your hardware documentation.
You can disable ACPI Soft-Off by configuring the BIOS of each cluster node as follows:
- Reboot the node and start the
BIOS CMOS Setup Utility
program. - Navigate to themenu (or equivalent power management menu).
- At the Example 3.1, “menu, set the function (or equivalent) to (or the equivalent setting that turns off the node by means of the power button without delay).
BIOS CMOS Setup Utility
: set to ” shows a menu with set to and set to .Note
The equivalents to, , and may vary among computers. However, the objective of this procedure is to configure the BIOS so that the computer is turned off by means of the power button without delay. - Exit the
BIOS CMOS Setup Utility
program, saving the BIOS configuration. - When the cluster is configured and running, verify that the node turns off immediately when fenced.
Note
You can fence the node with thefence_node
command or Conga.
Example 3.1. BIOS CMOS Setup Utility
: set to
+---------------------------------------------|-------------------+ | ACPI Function [Enabled] | Item Help | | ACPI Suspend Type [S1(POS)] |-------------------| | x Run VGABIOS if S3 Resume Auto | Menu Level * | | Suspend Mode [Disabled] | | | HDD Power Down [Disabled] | | | Soft-Off by PWR-BTTN [Instant-Off | | | CPU THRM-Throttling [50.0%] | | | Wake-Up by PCI card [Enabled] | | | Power On by Ring [Enabled] | | | Wake Up On LAN [Enabled] | | | x USB KB Wake-Up From S3 Disabled | | | Resume by Alarm [Disabled] | | | x Date(of Month) Alarm 0 | | | x Time(hh:mm:ss) Alarm 0 : 0 : | | | POWER ON Function [BUTTON ONLY | | | x KB Power ON Password Enter | | | x Hot Key Power ON Ctrl-F1 | | | | | | | | +---------------------------------------------|-------------------+
This example shows
set to , and set to .