Other Considerations for Administrators

This section is applicable to repository file pool servers, but not dedicated CRR recovery servers or dedicated FIFO servers because IBM does not recommend doing control data or user data backups for dedicated CRR recovery servers or FIFO servers.

To use the FILEPOOL BACKUP command to back up a storage group, the administration machine may need to have its MAXCONN value increased. The MAXCONN value is specified in the OPTION control statement of the VM system directory entries for the virtual machine. MAXCONN determines the maximum number of IUCV connections for a virtual machine. The FILEPOOL BACKUP, FILEPOOL CLEANUP, and FILEPOOL RESTORE commands use the CP DASD Block I/O system service for reading and writing file pool minidisks. CP DASD Block I/O uses IUCV. The FILEPOOL FILELOAD command, when used to restore a number of files simultaneously, uses a separate IUCV connection for each file.

Existing virtual machines may already have a MAXCONN value specified. If not specified, MAXCONN defaults to 64.

Note:

The number of IUCV or APPC/VM connections a user machine can have to file pools for SFS type operations is limited to one half of the MAXCONN value. For example, if a user machine will need to have 50 active connections at the same time, you should set the MAXCONN value for this machine to 100.

You may also want to allocate a small work minidisk to the administration machine if it does not already have one. This minidisk would be needed for the administrator to back up or restore the storage group to which he or she is assigned (assuming, of course, the administrator is also an enrolled file pool user). The backup and restore operations for user storage groups (FILEPOOL BACKUP and FILEPOOL RESTORE commands) write temporary data (global variables) to a read/write file mode. During the backup or restore, users are unable to write to the storage group. So, if the administrator is backing up or restoring his or her own storage group, the administrator will need to temporarily access a minidisk as file mode A. The minidisk only needs to be a cylinder or two (1000 to 2000 blocks on FB-512 devices).