5.2.1 Prerequisites for a logical host environment

Shared disk

• A shared disk must be used that can be taken over from the primary server to the secondary server.

• The shared disk must be assigned before JP1 is started.

• The assignment of the shared disk must not be canceled while JP1 is running.

• The assignment of the shared disk must be canceled after JP1 is stopped.

• The shared disk must be locked so that multiple servers do not inadvertently use it.

• Files must be protected using a file system with the journal functionality or other measures so that the files will not be lost due to a system failure.

• Failovers must guarantee that the contents of all files are taken over correctly.

• Failovers must be forced to occur even when a process is using the shared disk during failover.

• Clustering software must be responsible for recovery upon the detection of any failure on the shared disk so that JP1 does not need to perform recovery. Clustering software must issue a start or stop request to JP1 if it is necessary to start or stop JP1 as part of recovery.

• Use storage connected via SCSI or SAN (Fibre) as the shared disk for JP1/Base. Do not use network connection disks (NFS, NAS, and others) as the shared disk. As performance varies depending on the disk, carry out investigations in advance.

Logical IP address

• Communication must be performed using a logical IP address that can be taken over.

• The logical IP address must be uniquely determined from the logical host name.

• The logical IP address must be assigned before JP1 is started.

• The logical IP address must not be deleted while JP1 is running.

• The correspondence between the logical host name and logical IP address must not be modified while JP1 is running.

• The logical IP address must be deleted after JP1 is stopped.

• Clustering software must be responsible for recovery upon the detection of a network failure so that JP1 does not need to perform a recovery. Clustering software must issue a start or stop request to JP1 if it is necessary to start or stop JP1 as part of recovery.