OAMplex and file systems

Although there is no benefit to configuring an OAMplex when using a file system, OAM does provide some limited support for using a file system within an OAMplex.

When a file system is to be used by OAM in an OAMplex, all systems in the OAMplex must meet the following requirements (in addition to those identified in OAMplex):

For any storage group that will include the file system sublevel, the object storage group definitions in the SCDS must be set to ENABLE for all systems in the OAMplex.
The SETDISK statements in the CBROAMxx member of PARMLIB must be identical for all systems in the OAMplex . To meet this requirement, it is recommended that the ONLYIF statement be used so that a single CBROAMxx member can be used by all systems in the OAMplex.
The file systems identified in the SETDISK statements must be available to all systems in the OAMplex because OAM file system operations could be performed from any system in the OAMplex. To do this, these file systems must be defined through z/OS UNIX as a shared file system. In a shared file system environment, a file system mounted by one system participating in a shared file system is accessible to all systems participating in the shared file system. Establishing a shared file system is described in z/OS UNIX System Services Planning.

OAM cannot detect or prohibit configurations that do not meet the requirements. An improper configuration can lead to unpredictable results.

OAMplex and Recall to Disk: There are cases when an OAMplex configuration will result in read requests being shipped from one system in the OAMplex to another system in the OAMplex. When the read request is the result of an application OSREQ RETRIEVE request, then it is possible that the object will need to be recalled to the disk level of the OAM storage hierarchy. Whether the object is recalled to the DB2 sublevel or file system sublevel of the disk level of the OAM storage hierarchy depends on the capabilities of both the originating system and the target system involved in the request and on the configuration of the target system:

If both systems are z/OS V1R13 or above, the recall disk sublevel (DB2 or file system) will be determined by the configuration in place on the target system, not the originating system, consistent with the existing protocol for other OAMplex related processing.
If both systems are not at z/OS V1R13 or above, the target system will recall the object to the DB2 sublevel.

OAMplex and file system deletion processing: In an OAMplex, it should be assumed that file system physical deletions could be performed by any system in the OAMplex. Physical file system deletions will be accomplished by processing the entries in the File System Delete Table. OAM determines which system will perform the physical file system deletions and the actual timing of the physical file system deletions.