When using PRIMECLUSTER in a VMware environment, only clustering (a virtual machine function) between guest OSes on multiple ESX hosts is available.
When an error occurs on an ESX host or a guest OS within a VMware environment, applications on that guest OS will no longer work. In clustering between guest OSes on multiple ESX hosts, with PRIMECLUSTER applied to guest OSes, when an error occurs, applications will failover from the active guest OS to a standby guest OS in the event of a failure, which creates a highly reliable guest OS environment.
When using shared disks and a failover occurs with guest OSes not completely stopped (e.g. when the OS is hanging), I/O fencing can be used for putting the unstopped guest OSes into the panic state and thereby securely stop guest OSes. Also, it is possible to prevent access from both guest OSes to the shared disk in order to effect a safe and secure failover.
Figure H.1 Cluster Systems in a VMware Environment
See
For details on VMware, see the documentation for VMware.
Note
Up to two nodes can be added to one cluster system.
Clustering between guest OSes on a single ESX host is not available.
Since cluster systems in a VMware environment check guest OS statuses via network paths (administrative LAN or interconnect) before effecting a failover, it may happen that guest OSes on which an error occurred are not completely stopped (e.g. when the OS is hanging). Therefore, when using shared disks, you should make sure to set up I/O fencing.
For using I/O fencing, shared disk devices must be managed by PRIMECLUSTER Global Disk Services (GDS).
I/O fencing must be set up at the earlier stage of configuring the cluster application.
If a failure in the cluster interconnect occurs, a forced shutdown of a node depending on the survival priority, and an automatic switchover are not made and each node enters the LEFTCLUSTER state. In this case, the system administrator needs to recover the LEFTCLUSTER state manually. Perform the procedure in "6.2 Recovering from LEFTCLUSTER" in the "PRIMECLUSTER Cluster Foundation (CF) Configuration and Administration Guide."
Do not place an ESX host under a cluster such as VMware HA, VMware FT, VMware DRS, or VMware DPM.
The following features are not available with virtual machines in which PRIMECLUSTER is to be installed:
VMware VMotion
VMware Storage VMotion
Migration with VMware vCenter Converter
Snapshot
Hot clone
Backup by Data Recovery
Backup by VCB
