Fence Device and Agent Information for Red Hat Enterprise Linux

Overview

Fencing is the disconnection of a node from shared storage. Fencing cuts off I/O from shared storage, thus ensuring data integrity. A fence device is a hardware device that can be used to cut a node off from shared storage. This can be accomplished in a variety of ways: powering off the node via a remote power switch, disabling a Fibre Channel switch port, or revoking a host's SCSI 3 reservations. A fence agent is a software program that connects to a fence device in order to ask the fence device to cut off access to a node's shared storage (via powering off the node or removing access to the shared storage by other means).

This article outlines many commercial fence devices and maps them to the  fence agents that support them. Where available, information on  specific firmware revisions is provided.

For more detailed information on fencing and fence devices, see the official product documentation:

NOTE:

• This is a comprehensive list of devices. Not all of these devices are supported in Red Hat Enterprise Linux or Red Hat Enterprise Virtualization. Refer to  to determine if a particular fence agent is supported on your product.
• Every SNMP fence agent has support for SNMP v1/2c/3.
• N/A in "Supports List Action" indicates that this device can only access one machine and is not capable of listing multiple outlets.
• Not every IPMI-capable device is listed here. Generally, if your device supports IPMI v1.5+ and IPMI over LAN,fence_ipmilan is supported for that device.
• Any device that has "yes" in the IPMI v1.5+ Support column can be used with the fence_ipmilan agent. In general, it is preferred to use the ipmilan agent on devices that properly implement IPMI. However, in some cases this is not possible due to incomplete implementations, firmware bugs, or blade chassis devices that require a slot/port parameter. In the cases where fence_ipmilan cannot be used, the native fence agent can be used instead.

Support Status

NOTE: This article does not comment on the supportability of the software fence agents that are shipped with Red Hat Enterprise Linux and Red Hat Enterprise Virtualization. It does list which specific hardware fence devices are supported for a given software fence agent. In order to determine if a particular hardware fence device is supported, first determine if the fence agent corresponding to that device is supported in the version of Red Hat Enterprise Linux or Red Hat Enterprise Virtualization that you are using via the information at . If the fence agent corresponding to your device is supported, then check to see if your specific model is supported via the below tables. The below tables contain hardware devices that might be either unsupported or in Technology Preview status. Check with the Fence Support Matrix article to determine if your fence agent (and therefore fence device) is supported.

Fence Device and Agent Matrix

Vendor / Fence Device	Fence Agent	Fence Type	Style	Connection Methods	Supports List Action	Tested On: Hardware / Firmware	SNMP Support	IPMI v1.5+ Support	Notes
IPMI v1.5+ Compliant Devices over LAN	ipmilan	Power	C + ipmitool	ipmi	N/A		no	yes
Virtualization (libvirt)	xvm	Virt Guest	C (client/server app)	custom protocol using multicast and libvirt remote connections	no		no	no
Virtualization (libvirt)	virt	Virt Guest	C (client/server app)	custom protocol using either multicast or serial vmchannel and QMF/libvirt	no		no	no
Virtualization (libvirt)	virsh	Virt Guest	python	libvirt remove connections	no		no	no
Virtualization (RHEVM)	rhevm	Virt Guest	python	RHEVM REST API	no		no	no
Virtualization (VMware)	vmware	Virt Guest	python + fencing lib + VMware utils + PerlVI based helper	Running vmrun/helper	yes		no	no
Virtualization (VMware)	vmware_soap	Virt Guest	python + fencing lib + python-suds	SOAP API	yes		no	no
SCSI 3 Persistent Reservations	scsi	LUN access	perl + sg3_utils	ioctls	N/A		no	no
General IF:MIB	ifmib	Network Port	python + SNMP fencing lib	snmp	yes		yes	no
APC	apc	External Power Switch	python + fencing lib	ssh + telnet	yes	AP7951 & AOS v2.7.0	yes	no
APC	apc	External Power Switch	python + fencing lib	ssh + telnet	yes	AP7941 & AOS v3.5.7	yes	no
APC	apc	External Power Switch	python + fencing lib	ssh + telnet	yes	AP9606 & AOS v2.5.4	yes	no
APC	apc_snmp	External Power Switch	python + SNMP fencing lib	snmp	yes		yes	no
Baytech / RPC	baytech	External Power Switch	perl	telnet (ssh, kermit possible)	no	RPC27-20nc + Cyclades TS	yes	no
Blade Technologies / Rackswitch	rackswitch	External Power Switch	C	telnet-like	no
Brocade	brocade	Fibre Channel Port	perl	telnet	no		yes	no
Bull / NovaScale	bullpap	Power	perl	PAP console (using vendor tools)	no		yes	no
Cisco MDS	cisco_mds	Network Port	python + SNMP fencing lib	snmp	yes		yes	no
Cisco UCS	cisco_ucs	Power	python + fencing lib	http	yes		no	yes
Dell / DRAC 3 & DRAC/MC	drac	Power	perl	telnet	no	DRAC/MC & v1.1, v1.2, v1.3	read-only	no (some models)
Dell / DRAC 4	drac	Power	perl	telnet	no	DRAC 4/I & v1.0, v1.40	yes	no (some models)
Dell / DRAC 5 / CMC	drac5	Power	python + fencing lib	ssh + telnet	N/A	DRAC 5 & v1.0, v1.21	yes	yes
Dell / iDRAC (DRAC 6)	ipmilan	Power	C + ipmitool	ipmi	no		no	yes
Egenera	egenera	Power	perl	ssh	no		yes	no
ePowerSwitch	eps	Power	python + fencing lib	http	yes	ePowerSwitch 8M+ & v1.0.0.4	some models
Fujitsu / RSB	rsb	Power	python + telnet lib	telnet	no		yes	no (some models)
HP / iLO, iLO2	ilo	Power	python + fencing lib	https (-z added always)	N/A	iLO & 1.91, iLO2 & 1.22, 1.50	yes	yes
HP / iLO MP	ilo_mp	Power	python + fencing lib	ssh + telnet	N/A	iLO2 MP	yes	yes
HP / iLO3, iLO4	ipmilan	Power	C + ipmitool	ipmi	no		no	yes
IBM / BladeCenter	bladecenter	Power	python + fencing lib	ssh + telnet	yes	firmware BRET58K rev 16	yes	no
IBM / BladeCenter	ibm_blade	Power	python + SNMP fencing lib	snmp	yes		yes	no
IBM / LPAR	lpar	Power	python + fencing lib	ssh + telnet	yes	HMC v3, HMC v4	no	no
IBM / RSA	rsa	Power	python + fencing lib	ssh + telnet	N/A		yes	yes
Intel / Modular Server System	intelmodular	Power	python + SNMP fencing lib	snmp	yes	MFSYS25 & v2.6	yes	yes
Intel / IMM	ipmilan	Power	C + ipmitool	ipmi	no		no	yes
McDATA	mcdata	Fibre Channel Port	perl	telnet	no	firmware v01.03.00 v02.00.00 v04.01.00	yes	no
QLogic / SANbox	sanbox2	Fibre Channel Port	python + fencing lib	ssh + telnet	yes		yes	no
Sun / ILOM	ipmilan	Power	C + ipmitool	ipmi	no		no	yes
Vixel (Emulex)	vixel	Fibre Channel Port	perl	telnet	no		yes
WTI Remote Reboot PDUs	wti	External Power Switch	python + fencing lib	ssh + telnet	yes	RSM-8R4, MPC-8H, IPS series, VMR-8, NPS series	yes	no
WTI Serial Power Control Devices	rps10	External Power Switch	C	serial RS232	no	RPS-10HD	no	no

Notes:
1. ipmitool works with IPMI v1.5 and v2.0+
2. RHEL 5.7+, RHEL 6.2+.  Red Hat Enterprise Virtualization 3 or later.
3. fence_vmware is not supported. It was superseded by fence_vmware_soap. See .
4. RHEL 5.7+, RHEL 6.2+.  VMware vSphere ESX 4.1.  Version 5.0 .
5. Fibre Channel or iSCSI SAN storage: SAN device must be SCSI3 Persistent Reservation Compliant with support forpreempt-and-abort command. See  for more information.
6. SSH has to be set to protocol 1 and des/blowfish cipher different menu for admin/user (valid for every APC)
7. Cisco MDS 9124 & 9134 (RHEL 5.4+)
8. The Cisco UCS blades do support ipmi-based fencing, but this requires connecting to each blade individually. The Cisco UCS-based fence agent allows fencing to be done by connecting to the UCS chassis and specifying the blade by name.
9. ipmi over LAN support may be disabled by default on iDRAC/DRAC6 hardware. Follow the manufacturer's instructions for enabling ipmi over LAN support so that the fence_ipmilan agent will work.
10. fence_ipmilan can also be used with iLO2 version 2.00 and later.
11. fence_ipmilan must be used with the -P option to enable Lanplus. It also requires usage of the -T parameter to provide at least a 4 second timeout rather than the default fence_ipmilan default of 2 seconds. The -T parameter is provided in versions of fence_ipmilan from Red Hat Enterprise Linux 5.5.z and up.
12. According to the manual, SNMP access is read-only, but it is in fact read-write. IPMI v2 compatible.
13. When using SSH, sometimes it is necessary to set login_timeout to 10. NPS models are supported with RHEL 5.7, 6.1, and later.
14. Two-node clusters only.
15. Newer revisions of APC switched rack PDUs, particularly those with ., are not known to work well with fence_apc. Please use  instead. The AOS version can be seen immediately after logging in.

Supported External Fence Device Models

Manufacturer	Model
APC	Switched Rack PDU AP7902, AP7902J
APC	Switched Rack PDU AP7930, AP7998
APC	Switched Rack PDU AP7900
APC	Switched Rack PDU AP7901
APC	Switched Rack PDU AP7911, AP7911A
APC	Switched Rack PDU AP7920
APC	Switched Rack PDU AP7921
APC	Switched Rack PDU AP8941 (using SNMP)
WTI	IPS-15
WTI	IPS-1600
WTI	IPS-1600-CE
WTI	IPS-400
WTI	IPS-400-CE
WTI	IPS-800
WTI	IPS-800-CE
WTI	MPC-8H (5.3)
WTI	NBB-1600
WTI	NBB-1600-CE
WTI	RPS-10 Series (Note: Two-node clusters only)
WTI	RSM-8R4
WTI	TPS-2
WTI	NPS Series
WTI	VMR Series

Supported SAN-Based Fence Device Models

Manufacturer	Model
Brocade	Silkworm 2400
Brocade	Silkworm 2800
Brocade	Silkworm 3200
Brocade	200E
Brocade	300
Brocade	4100
Brocade	4900
Brocade	5100
Brocade	5480
Dell	PowerVault 56F
McData	Sphereon 4500
Vixel	9200