Available I/O Fencing Mechanisms (Virtual Machines in VMware)

This page describes the combinations of fencing mechanisms that can be used with various storage configurations in a VMware virtual server environment.

Shared Disk Configuration (Single or Multipath Configuration Using SCSI Reservations)

This configuration corresponds to the case where exclusive control is enforced by SCSI reservations in a certified shared storage system, as listed in the Supported Storage List. When using storage that requires a multipath driver for SCSI-3 reservations and multipath control, a multipath kit that supports the multipath driver is required.

Available Fencing Mechanisms

The following table shows which fencing mechanisms are available and the allowed combinations, if multiple fencing mechanisms are used.

Symbol Definitions

⬤ – Required
◯ – Available as an option
❌ – Not available

For the functions listed as “Available as an option” in the table, use of the functions in the combination is not mandatory. Please refer to the note below the table for the functions that are “Not available” in the table.

¹ SCSI-2 and SCSI-3 reservations cannot coexist on a single shared disk.
² When SCSI Reservations and STONITH are used together, the functions of each may conflict and an unexpected system outage may occur.
³ Multiple Quorum/Witness modes cannot be used together in a single cluster.

Mechanisms Not Available with this Configuration

• Fencing mechanisms for virtual environments other than VMware cannot be used with this configuration.
• Fencing mechanisms for cloud and physical environments cannot be used with this configuration.

Shared Disk Configuration (Single or Multipath Configuration Not Using SCSI Reservations)

This configuration is applicable when SCSI reservations cannot be used with a shared storage system connected with a method including SCSI/FC/iSCSI/SAS (but excluding NAS). When using storage that requires a multipath driver to control multiple paths, a multipath kit that supports the multipath driver is required.

Available Fencing Mechanisms

The following table shows which fencing mechanisms are available and the allowed combinations, if multiple fencing mechanisms are used.

Symbol Definitions

⬤ – Required
◯ – Available as an option
❌ – Not available

For the functions listed as “Available as an option” in the table, use of the functions in the combination is not mandatory. Please refer to the note below the table for the functions that are “Not available” in the table.

¹ Multiple Quorum/Witness modes cannot be used together in a single cluster.

Mechanisms Not Available with this Configuration

• SCSI Fencing cannot be used with storage systems that are not certified to properly support SCSI reservations.
• Fencing mechanisms for virtual environments other than VMware cannot be used with this configuration.
• Fencing mechanisms for cloud and physical environments cannot be used with this configuration.

Data Replication Configuration

This configuration is applicable when local storage connected to each node is replicated between nodes using DataKeeper.

Available Fencing Mechanisms

The following table shows which fencing mechanisms are available and the allowed combinations, if multiple fencing mechanisms are used. Fencing is not mandatory in this configuration; however, it is recommended to use fencing to enhance data protection.

Symbol Definitions

⬤ – Required
◯ – Available as an option
❌ – Not available

For the functions listed as “Available as an option” in the table, use of the functions in the combination is not mandatory. Please refer to the note below the table for the functions that are “Not available” in the table.

¹ Multiple Quorum/Witness modes cannot be used together in a single cluster.

Mechanisms Not Available with this Configuration

• SCSI Fencing cannot be used with this configuration.
• Fencing mechanisms for virtual environments other than VMware cannot be used with this configuration.
• Fencing mechanisms for cloud and physical environments cannot be used with this configuration.

Network Attached Storage (NAS) Configuration

This configuration is applicable when using NAS storage connected using Network File System (NFS).

Available Fencing Mechanisms

The following table shows which fencing mechanisms are available and the allowed combinations, if multiple fencing mechanisms are used. Fencing is not mandatory in this configuration; however, it is recommended to use fencing to enhance data protection.

Symbol Definitions

⬤ – Required
◯ – Available as an option
❌ – Not available

For the functions listed as “Available as an option” in the table, use of the functions in the combination is not mandatory. Please refer to the note below the table for the functions that are “Not available” in the table.

¹ Multiple Quorum/Witness modes cannot be used together in a single cluster.

Mechanisms Not Available with this Configuration

• SCSI Fencing cannot be used with this configuration.
• Fencing mechanisms for virtual environments other than VMware cannot be used with this configuration.
• Fencing mechanisms for cloud and physical environments cannot be used with this configuration.

VMDK as Shared Storage Configuration

This configuration is applicable when using a VMware virtual hard disk configured with the VMDK as the Shared Storage method.

Available Functions and Appropriate Combinations

The table below shows the fencing functions available with this configuration and the appropriate combination patterns.

Symbol Definitions

⬤ – Required
◯ – Available as an option
❌ – Not available

For the functions listed as “Available as an option” in the table, use of the functions in the combination is not mandatory. Please refer to the note below the table for the functions that are “Not available” in the table.

¹ VMDK as Shared Storage and VMware STONITH cannot coexist because service may stop due to a conflict.
² Due to the LifeKeeper mechanism, Quorum Witness modes cannot coexist for a single cluster.

Unavailable Function with this Configuration

• The fencing function that requires the use of a shared disk cannot be used with this configuration.