File Pool Server Machines

A file pool server machine is a virtual machine that has been set up with the following characteristics:

Owns the minidisks assigned to a file pool or at least has write authority to the minidisks.
Has z/VM system directory control statements that let it communicate with other virtual machines.
Has 32MB of virtual storage, which is adequate for most file pool server machines. XC mode is recommended.
Has read access to the minidisk on which the FILESERV commands reside. (The FILESERV commands are discussed in this section.) The commands reside on the MAINT 193 minidisk.
Has read/write access to a CMS minidisk (usually accessed as file mode A). The read/write space is used for the POOLDEF file as well as for temporary work files.

The four IBM-supplied file pool server machines are named VMSERVS, VMSERVP, VMSERVU, and VMSERVR. The VMSERVS machine owns the minidisks for the VMSYS file pool, which contains system files. The VMSERVP machine owns the minidisks for the VMPSFS file pool, which contains product service files. The VMSERVU machine owns the minidisks for the VMSYSU file pool, which is for your use. The VMSERVR machine owns the minidisks for the VMSYSR file pool, which is for the CRR recovery server. These server machines have all of the preceding characteristics. Generating a File Pool and Server describes how to create additional server machines and file pools.

Aside from the preceding characteristics, the virtual machine is quite ordinary. It has a console and the usual virtual devices—reader, punch, printer, tapes—and perhaps owns additional minidisks. It may also have access to a file space in another file pool. Of particular interest is the server operator console. Figure 1 shows a file pool, a file pool server machine, and a file pool server machine operator console. (The actual display device can be any that z/VM supports.)

Shows a file pool, a file pool server machine, and a file pool server machine operator console. — Figure 1. A File Pool Server Machine Operator Console

For brevity, the file pool server machine operator console is referred to as the operator console. From the operator console, you can enter FILESERV commands, which operate on a file pool. (CMS must be running in the file pool server machine before any FILESERV command can be entered.)

All FILESERV commands, except one, perform maintenance operations on a file pool. When a maintenance command is running against a file pool, the file pool is not available to other users. Because of this, the commands are known as dedicated maintenance mode commands. All file pool server dedicated maintenance mode commands are listed in Table 1.

When any of the commands in Table 1 is entered, the server machine is running in dedicated maintenance mode. When the command completes, dedicated maintenance mode ends.

Table 1. Dedicated Maintenance Mode Commands
Command	Function
FILESERV BACKUP	Makes a backup copy of the file pool control data (which is the POOLDEF file, the control minidisk, and the catalog storage group)
FILESERV CRRLOG (CRR-only)	Reconfigures the CRR log minidisks
FILESERV DEFBACKUP	Defines the output file for subsequent backups
FILESERV DEFAUDIT	Defines the output file for any subsequent security audit trace
FILESERV DEFCRRLOG	Updates CRR log minidisk definitions in the CRR recovery server's POOLDEF file
FILESERV GENERATE	Generates a new file pool
FILESERV LIST	Lists the contents of the file pool catalogs
FILESERV LOG	Reconfigures the file pool log minidisks
FILESERV MINIDISK	Adds storage group minidisks to a file pool
FILESERV MOVEUSER	Move a user or file space from one storage group to another
FILESERV REGENERATE	Expands the maximum size of a file pool
FILESERV REORG	Reorganizes the file pool catalogs for better performance

You can control various aspects of FILESERV command processing by specifying startup parameters in a CMS file. Because this file's file type must be DMSPARMS, a file containing startup parameters is often referred to as DMSPARMS files. All startup parameters are described in File Pool Server Startup Parameters.

You do not need to memorize the list of FILESERV commands or the startup parameters that can be used with them. Later chapters in this manual describe all the FILESERV dedicated maintenance mode commands and tell you when they should be used and with which startup parameters.

Only one FILESERV command, named FILESERV START, is not a dedicated maintenance mode command. It is the command that starts the server for multiple user access. When you enter FILESERV START, the file pool is opened for service through communications from other user or client virtual machines, which means users and applications can create and access files in the file pool. For SFS it also means that participating applications can perform CRR logging for coordinated transaction processing. The server is said to be running in multiple user mode, which is shown in Figure 2.

When the server is running in multiple user mode, it cannot be used for other applications. Multiple user mode processing requires the continual use of the virtual machine. Therefore, after entering FILESERV START, you will usually want to run the server in disconnected mode. In disconnected mode, the server virtual machine continues operation, but your terminal is disconnected from the z/VM system. (See the CP DISCONN command in z/VM: CP Commands and Utilities Reference.)

When you disconnect from a virtual machine, any messages generated by that machine are usually lost. (Because you have disconnected your terminal, there is no place for the messages to be displayed.) For some applications, it does not matter whether the messages it generates are lost. Server messages, however, are important and should not be lost or ignored.

To avoid losing server messages, the use of the Single Console Image Facility (SCIF) is strongly recommended. SCIF lets you define a secondary user to which all messages are sent when a virtual machine (known as the primary user) is running in disconnected mode. In this case, the server machine is the primary user. When the server is running in disconnected mode, all server messages appear on the console of the secondary user. Figure 3 shows server operation when a primary user is running in disconnected mode.

Shows server operation when a primary user is running in disconnected mode. — Figure 3. Disconnected Server Operation

VMSERVS, VMSERVP, VMSERVU, and VMSERVR file pool server machines are set up so that MAINT is the secondary user. When VMSERVS, VMSERVP, VMSERVU, or VMSERVR is running in multiple user mode and is disconnected, all of their messages are routed to the console of the MAINT machine. Assuming that MAINT is logged on, the messages are displayed with a prefix that lets you know where the message is from. If MAINT (or any other defined secondary user for the server) is not logged on or is running in disconnected mode, the messages are lost. You can save the server's messages, even though the secondary user is not logged on or is running in disconnected mode, by using the CP SPOOL CONSOLE command in the server's and secondary user's PROFILE EXEC. For more information, see Post-installation Activities.

Some server messages require a response. To reply to a message from a secondary user console, use the CP SEND command. (Instructions for using the CP SEND command are in Operation.) You can also use the CP SEND command to enter server operator commands.

Server operator commands let you control multiple user mode execution, and CRR processing. They can be used only after FILESERV START has been issued and the server has completed its initialization process. You can enter them at the server machine console or from its secondary user console. All file pool repository and CRR recovery server operator commands are listed in Table 2.

Table 2. File Pool Repository and CRR Operator Commands
Command	Function
AUDIT	Starts an audit trace of security. (During an audit trace, the server records information about file pool usage and about operator intervention into CRR activity in a file. Later you can format and review the information in the file to determine if there were any unauthorized attempts to use file pool resources or to intervene into CRR activity).
BACKUP	Makes a backup copy of the file pool control data.
CRR (CRR-only)	Allows operator to do CRR log management, problem management, and resynchronization management.
DEFBACKUP	Defines the output file for subsequent control data backups.
DISABLE	Prevents users from accessing a particular storage group or file space.
ENABLE	Allows access to a previously disabled storage group or file space.
ERASE LUNAME (CRR-only)	Removes history of all previously forced SFS logical units of work from the file pool logs.
ETRACE	Starts or stops an external trace of server machine execution. (Records are written to a CP spool file.)
FORCE	Stops a user's current work with the file pool, and commit or roll back SFS prepared work.
GRANT ADMIN	Grants file pool administration authority to another user.
ITRACE	Starts or stops an internal trace, during which records are written to an internal buffer, of server APPC/VM communication activity.
QUERY DEFBACKUP	Shows the current default assignment for the control data backup file, or shows the destination where the last backup file was created.
QUERY DISABLE	Tells whether a storage group or file space is disabled and who disabled it.
QUERY LOGTABLE (CRR-only)	Display the specified LU name and transaction program name (TPN) for entries in the SFS log name table.
QUERY PREPARED (CRR-only)	Display information about SFS prepared work and forced work.
REVOKE ADMIN	Revokes file pool administration authority from a user.
STOP	Stops multiple user mode processing.

For brevity, file pool server operator commands are referred to, simply, as operator commands. This manual describes all the operator commands in later chapters.

If you scanned the commands in Table 2, you may have noticed the term file pool administration authority. File pool administration authority is a special authority. Those who have it can control file pool resources and can read from or write to other users' files and directories. Remember, though, that the person who controls the operator console has the keys to the file pool server machine and the file pool. That person can grant file pool administration authority to any other user, and has access to all the file pool minidisks.