DB2 Server for VM: System Administration

Running the Database Manager

When you use the database manager, you should be aware of the following:

• Saved segments are defined using VMSES/E.
• The resource adapter and the RDS component can be saved above the 16 megabyte line.

  For more information, see Defining Saved Segments.

• Operating modes

  Your virtual machine can be set to XA/ESA mode or XC mode. If certain components are defined as saved segments, they must be saved below the 16 megabyte virtual storage line. (The exceptions are the resource adapter and RDS, which can be saved above the 16 megabyte line.) The AMODE parameter specifies the type of addressing the database manager runs in. For more information, see Starting the Application Server in Multiple User Mode.

  A user machine can run in XA/ESA mode or XC mode. It can take advantage of a resource adapter saved segment saved above the 16 megabyte virtual storage line.

  User application programs can take advantage of 31- or 24-bit addressing, and reside above or below the 16 megabyte virtual storage line.

  For more information on running application programs in either XA/ESA or XC mode, see the DB2 Server for VSE & VM Application Programming manual.

• The following facilities are available:
  • VSE guest sharing
  • CMS work unit support
  • Database switching
  • Remote unit of work
  • Distributed unit of work.

Operating Modes

You set the virtual machine operating mode in the machine's CMS directory, or with the SET MACHINE command. Users can issue this command for their virtual machines, and the operator issues it for the database machine. For more information on this command, see the VM/ESA: CMS Command Reference manual.

Table 6 shows how features can take advantage of the VM/ESA ESA Feature.

Table 6. Summary of Support

	AMODE		RMODE
	24	31	24	ANY
RA/DRRM/CONV	X	X	X	X 1
DSC	X	X 2	X
RDS/DRRM/WUM/CONV	X	X	X	X
DBSS	X	X 2	X
ISQL	X		X
DBSU	X 3		X
Preprocessors	X 3		X
User Applications	X	X 4	X	X 4

Notes:

1. The resource adapter (RA) runs AMODE(31) RMODE(ANY). It does not depend on the AMODE parameter.

2. This DB2 Server for VM code must reside below the 16 megabyte line. However, most dynamic storage is allocated above it (if available).

3. In single user mode, if the database manager is running AMODE(31), it automatically switches to AMODE(24) when the preprocessor or DBSU is invoked by the database manager. The AMODE is then switched back to AMODE(31) after returning control to the database manager.

4. For more information, refer to Starting the Application Server in Multiple User Mode, Starting the Application Server in Single User Mode, and Chapter 14, Creating Installation Exits.