DB2 Server for VM: System Administration

Migrating from a VM/XA to a VM/ESA Environment

You can migrate your VM/XA databases to a VM/ESA operating system in two ways:

You may have to update the SNA NETID file. See Updating the SNA NETID File.

Delaying the Directory and Database Name Changes

If you have just installed a VM/ESA operating system, and you want to delay the directory and database naming changes, you can operate your database machines in non-APPC/VM mode. In this mode, IUCV is used and the remote unit of work and database switching capabilities are not available.

To indicate that the database machine is to use IUCV communication paths instead of APPC/VM, set the DBMODE initialization parameter to N when you start the application server. This connects you to an application server using the database machine's VM ID. Otherwise, APPC/VM paths will be used, and you will be connected to the application server using the resource identifier (resid).

If you have already made the directory changes and database name changes, do not set DBMODE to N.

Setting up the Database Machine Directory Entry

To use Version 6 Release 1, ensure that you have the necessary VM directory control statements. An example of these statements is shown in Figure 3.
Note:Only those statements that differ from the ones used in the VM/XA operating system are explained following the figure. For details of the other statements, see Adding a Primary Database Machine.

Figure 3. Example VM Directory Control Statements for the SQLMACH Machine

1 ---> USER SQLMACH sqlmachpw xM xM G
       ACCOUNT nnnnnnnn
2 ---> OPTION MAXCONN 26
       IUCV ALLOW
3 ---> IUCV *IDENT SQLDBA GLOBAL
       IPL CMS PARM AUTOCR
       CONSOLE 009 3215 T OPERATOR
       SPOOL 00C 2540 *
       SPOOL 00D 2540 A
       SPOOL 00E 1403
       LINK MAINT 190 190 RR
       LINK MAINT 19D 19D RR
       MDISK 191 3380 cylr 010 volser W
       MDISK 193 3380 cylr 060 volser R rsql wsql
       MDISK 195 3380 cylr 020 volser RR rsql wsql msql
       MDISK 200 3380 cylr 034 volser R rsql wsql
       MDISK 201 3380 cylr 008 volser R rsql wsql
       MDISK 202 3380 cylr 077 volser R rsql wsql

Statement 1: USER SQLMACH sqlmachpw xM xM G

This statement defines the database machine SQLMACH with the VM privilege class G. The recommended minimum size required for SQLMACH is 8MB for the base code only, or for the base code and the DSS code. If the DRDA code is installed, the recommended minimum size is 10MB.

Statement 2: OPTION MAXCONN 26

The MAXCONN value must be increased by 1 (over that specified for the VM/XA operating system), because the machine now makes one additional IUCV connection to *IDENT.

The default value for MAXCONN is 4 in the VM/XA operating system, and 16 in the VM/ESA operating system.

Statement 3: IUCV *IDENT SQLDBA GLOBAL

In a VM/ESA operating system, the database machine is the resource owner, so it must be authorized to connect to the VM system service *IDENT. This authorization is granted by the IUCV entry in the database machine directory. The name of the database (specified in the DBNAME parameter of the SQLDBINS EXEC) is used as the resource identifier.

Figure 4 shows the syntax of the IUCV *IDENT statement.

Figure 4. IUCV *IDENT Syntax

>>-IUCV *IDENT----+-------------+---+-------------+------------><
                  +-+-------+---+   +-+-------+---+
                  | '-resid-'   |   | '-LOCAL-'   |
                  '-+--------+--'   '-+--------+--'
                    '-RESANY-'        '-GLOBAL-'

resid
This variable is the resource identifier of an application server that can be started in this virtual machine. The machine can have multiple resid entries in its directory. (In Figure 3, the resid is SQLDBA.) Usually, the resid is the server name of the application server. However, if the resid and the server name are different, they must both be defined in the RESID NAMES file during database generation.

RESANY
This parameter enables the database machine to identify any resource identifier as either a LOCAL or GLOBAL resource. Specify it if you want to access more than one application server (accessed one at a time).

LOCAL
This parameter ensures that only the application requesters that are on the same processor as the database machine can use this application server

GLOBAL
This parameter identifies an application server as a resource that can be accessed by all application requesters in a network.

Example of a Database Machine Directory with Multiple Databases

Figure 5 shows the control statements in the directory of a database machine with multiple databases. This database machine can manage three application servers on this processor, but only one at any given time. The three database resids in this example are SQLRES1, SQLRES2, and SQLRES3. The first two can only be accessed by users on the local processor, while the third can be accessed by both local and remote users.

Figure 5. Database Machine Directory Entries

  ---> USER SQLMACH sqlmachpw xM xM G
       ACCOUNT nnnnnnnn
       OPTION MAXCONN 26
       IUCV ALLOW
  ---> IUCV *IDENT SQLRES1 LOCAL
  ---> IUCV *IDENT SQLRES2 LOCAL
  ---> IUCV *IDENT SQLRES3 GLOBAL
       IPL CMS PARM AUTOCR
       CONSOLE 009 3215 T OPERATOR
       SPOOL 00C 2540 *
       SPOOL 00D 2540 A
       SPOOL 00E 1403
       LINK MAINT 190 190 RR
       LINK MAINT 19D 19D RR
       MDISK 191 3380 cylr 010 volser W
       MDISK 193 3380 cylr 060 volser R rsql wsql
       MDISK 195 3380 cylr 020 volser RR rsql wsql msql
       MDISK 200 3380 cylr 034 volser R rsql wsql
       MDISK 201 3380 cylr 008 volser R rsql wsql
       MDISK 202 3380 cylr 077 volser R rsql wsql
       MDISK 203 3380 cylr 034 volser R rsql wsql
       MDISK 204 3380 cylr 008 volser R rsql wsql
       MDISK 205 3380 cylr 077 volser R rsql wsql
       MDISK 206 3380 cylr 034 volser R rsql wsql
       MDISK 207 3380 cylr 008 volser R rsql wsql
       MDISK 208 3380 cylr 077 volser R rsql wsql

Setting Up the User Machine Directory Entry

In a VM/ESA operating system, the database manager uses advanced-program-to-program-communications/virtual machine (APPC/VM) in place of IUCV. User machines connect to a resource, not to the database machine. A change is required if access to the resource had been controlled by specifying IUCV dbmachid in the directory entries of the user machines. The IUCV dbmachid must be replaced with the IUCV resid statement in each virtual machine directory, to allow the user machine to connect to the application server identified as a resource. Figure 6 shows an example of the VM directory entry for a user machine.
Note:Only those statements that differ from the ones used in the VM/XA operating system are explained following the figure. For information on user machine directory entries, see Defining Additional User Machines. For a complete description of VM directory control statements, refer to the VM/ESA: Planning and Administration manual.

Figure 6. Example VM Directory Entries for a User Machine

1 ---> USER SQLUSER sqluser xM xM G
       ACCOUNT nnnnnnnn
2 ---> IUCV resid
       IPL CMS PARM AUTOCR
       CONSOLE 009 3215
       SPOOL 00C 2540 *
       SPOOL 00D 2540 A
       SPOOL 00E 1403
       LINK MAINT 190 190 RR
       LINK MAINT 19D 19D RR
       MDISK 191 3380 cylr 003 volser W
       LINK SQLMACH 195 195 RR

Statement 1: USER SQLMACH sqlmachpw xM xM G

This statement defines the user machine with the VM privilege class G. The user machine requires 6 megabytes.

Statement 2: IUCV resid (used for the VM/ESA operating system)

This statement is only required if the IUCV ALLOW control statement is not present in the VM directory for the database machine (SQLMACH). Since the default arrangement is for IUCV ALLOW to be specified in the VM directory entry for the database, most users omit this statement. If you later decide to have more control over user machine-to-application server communications, you can change the IUCV control statements.

Figure 7 shows the syntax of the IUCV statement used for the VM/ESA operating system.

Figure 7. IUCV Statement Syntax

>>-IUCV----+-----------+---------------------------------------><
           +-+-----+---+
           | '-ANY-'   |
           +-resid-----+
           '-gatewayid-'

ANY
This parameter authorizes the user machine to connect to any application server identified as a resource.

resid
This variable authorizes a user machine to connect only to the application server identified by resid. If more than one IUCV resid statement is specified in the machine's directory, the user machine can communicate with more than one application server.

gatewayid
This variable authorizes the user machine to connect to the resources in an SNA network through gatewayid, rather than to a specified virtual machine.

For more information about the VM directory control statements that affect intermachine communications, see VM Directory Control Statements.

Database Naming Considerations

You may have to change the names of your databases (server-name), to ensure that they are unique within a set of interconnected SNA networks, and that their resids are unique in a TSAF collection or gateway. For more information, see Distributed Processing Security.

When you migrate a database from a VM/XA to a VM/ESA operating system you can specify a value for server-name of up to 18 characters, and a value for resid of up to 8 characters. For more information, see Choosing an Application Server Name and VM Resource Identifier.

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