I/O fencing protects the data on shared disks when nodes in a cluster detect a change in the cluster membership that indicates a split-brain condition.
The fencing operation determines the following:
The nodes that must retain access to the shared storage
The nodes that must be ejected from the cluster
This decision prevents possible data corruption. The installer installs the I/O fencing driver, VRTSvxfen, when you install SFCFSHA. To protect data on shared disks, you must configure I/O fencing after you install and configure SFCFSHA.
I/O fencing technology uses coordination points for arbitration in the event of a network partition.
I/O fencing coordination points can be coordinator disks or coordination point servers (CP servers) or both. You can configure disk-based or server-based I/O fencing:
Disk-based I/O fencing |
I/O fencing that uses coordinator disks is referred to as disk-based I/O fencing. Disk-based I/O fencing ensures data integrity in a single cluster. |
Server-based I/O fencing |
I/O fencing that uses at least one CP server system is referred to as server-based I/O fencing. Server-based fencing can include only CP servers, or a mix of CP servers and coordinator disks. Server-based I/O fencing ensures data integrity in multiple clusters. In virtualized environments that do not support SCSI-3 PR, SFCFSHA supports non-SCSI-3 server-based I/O fencing. See About I/O fencing for SFCFSHA in virtual machines that do not support SCSI-3 PR. |
See About preventing data corruption with I/O fencing.
Note: |
Symantec recommends that you use I/O fencing to protect your cluster against split-brain situations. |
See the Veritas Storage Foundation Cluster File System High Availability Installation Guide.