8 Installing with DB2 z/OS Databases

The following system services must be enabled on the host system.

• Activate UNIX System Services (USS) in full function mode rather than in minimum mode. You can use the DB2 z/OS UNIX Configuration Wizard for this purpose. Refer to the IBM UNIX System Services Planning manual for more information. The UNIX customization includes the following:

  • Make the Language Environment run-time library (RTL) available to Oracle GoldenGate and other C programs by including it in the link list or Link Pack Area (LPA), or by adding it to the STEPLIB environment variable. RTL consists of data sets SCEERUN and SCEERUN2. If you are using STEPLIB , define the SCEERUN data sets to LLA to make loading the run-time modules faster. See the UNIX System Services Planning documentation for more information.

• Install Recoverable Resource Manager Services (RRS) for the best performance. Depending on the attachment type, the user by which Oracle GoldenGate runs might need one of the following permissions on the DSNR resource class:

  • If using RRSAF, assign RACF ACCESS(READ) to the RRSAF resource. IBM recommends using RRSAF because it has several advantages over CAF, including support for two-phase commit, thread reuse, and control over accounting intervals.

  • If using CAF, assign RACF ACCESS(READ) to the BATCH environment. If using CAF, it is possible for Oracle GoldenGate to hold locks on the system catalog until it receives a transaction commit.

• Oracle GoldenGate supports Sysplex data sharing.

Oracle GoldenGate requires the following memory resources on the local system.

On the remote system

The amount of memory that is required for Oracle GoldenGate depends on the amount of data being processed, the number of Oracle GoldenGate processes running, the amount of RAM available to Oracle GoldenGate, and the amount of disk space that is available to Oracle GoldenGate for storing pages of RAM temporarily on disk when the operating system needs to free up RAM (typically when a low watermark is reached). This temporary storage of RAM to disk is commonly known as swapping or paging. Depending on the platform, the term swap space can be a swap partition, a swap file, or a shared memory segment (IBM i platforms).

Modern servers have sufficient RAM combined with sufficient swap space and memory management systems to run Oracle GoldenGate. However, increasing the amount of RAM available to Oracle GoldenGate may significantly improve its performance, as well as that of the system in general.

Typical Oracle GoldenGate installations provide RAM in multiples of gigabytes to prevent excessive swapping of RAM pages to disk. The more contention there is for RAM the more swap space that is used.

Excessive swapping to disk causes performance issues for the Extract process in particular, because it must store data from each open transaction until a commit record is received. If Oracle GoldenGate runs on the same system as the database, the amount of RAM that is available becomes critical to the performance of both.

RAM and swap usage are controlled by the operating system, not the Oracle GoldenGate processes. The Oracle GoldenGate cache manager takes advantage of the memory management functions of the operating system to ensure that the Oracle GoldenGate processes work in a sustained and efficient manner. In most cases, users need not change the default Oracle GoldenGate memory management configuration.

For more information about evaluating Oracle GoldenGate memory requirements, see the CACHEMGR parameter in the Reference for Oracle GoldenGate.

On the DB2 host system

Allocate approximately 10-50 MB of virtual memory for each Oracle GoldenGate log reader, oggreadx, that is invoked depending on the size of the log buffer. There is one invocation per Extract process on the remote system. To adjust the maximum log buffer size, use the TRANLOGOPTIONS BUFSIZE parameter in the Extract parameter file.

(Only applicable if you are installing stored procedures.) When using TSO to access USS, give the TSO user enough memory allocation to start the Oracle GoldenGate GGSCI process. If the CEE3536S Not enough storage was available for the WSA error message occurs, increase the TSO user memory or ask your TSO administrator to do it.

This section outlines the disk requirements needed to support Oracle GoldenGate on DB2 z/OS.

On the remote system

Assign the following free disk space:

• To determine the size of the Oracle GoldenGate download file, view the Size column before downloading your selected build from Oracle Software Delivery Cloud. The value shown is the size of the files in compressed form. The size of the expanded Oracle GoldenGate installation directory will be significantly larger on disk.

• Allow at least an additional 1 GB of disk space on any system that hosts Oracle GoldenGate trails, which are files that contain the working data. You may need more or less than this amount, because the space that is consumed by the trails depends on the volume of data that will be processed. See the guidelines for sizing trails in Administering Oracle GoldenGate.

• By default, Oracle GoldenGate maintains data that it swaps to disk in the dirtmp sub-directory of the Oracle GoldenGate installation directory. The cache manager assumes that all of the free space on the file system is available. This directory can fill up quickly if there is a large transaction volume with large transaction sizes. To prevent I/O contention and possible disk-related Extract failures, dedicate a disk to this directory. You can assign a name and size to this directory with the CACHEDIRECTORY option of the CACHEMGR parameter. The CACHESIZE option of CACHEMGR sets a soft limit for the amount of virtual memory (cache size) that is available for caching transaction data. See Reference for Oracle GoldenGate for the default values of these options and detailed explanations, in case system adjustments need to be made.

On the DB2 host system

(Only applicable if you are installing stored procedures.) Assign a zFS (zSeries file systems) or hierarchical file system volume. To determine the size of the Oracle GoldenGate download file, examine the size of zOSPrograms.zip on the remote DB2 system after extracting the installation image.

The remote host requires privileges to use the chmod +rw command on the subdirectories in the Oracle GoldenGate product directory.

Table 8-1 shows the other required operating system privileges for Oracle GoldenGate:

^Footnote 1

Requires access to either the CAF or the RRSAF protected access profile in the DSNR RACF resource class, depending upon the MVSATTACHTYPE value in the ODBC initialization file.

^Footnote 2

Non-data sharing only.

^Footnote 3

In IBM DB2 10 for z/OS 1.13 and later.

Configure the following database components to support Oracle GoldenGate.

• Install a DB2 ODBC driver. The Oracle GoldenGate Extract and Replicat processes use ODBC (Open Database Connectivity) to connect to the DB2 subsystem. For information about ODBC, see the DB2 for z/OS ODBC Guide and Reference documentation.

• Install and configure the DB2 ODBC dynamic load library.

• Grant Oracle GoldenGate EXECUTE privilege on the plan that is specified in the ODBC initialization file (the default is DSNACLI).

• You might need to insert the name of the local DB2 subsystem into the SYSIBM.LOCATIONS table, which contains the remote DB2 server locations. Use a statement similar to the following (the example uses the name DB2A).

  INSERT INTO SYSIBM.LOCATIONS (LOCATION, PORT) VALUES ('DB2A', '446');
  

Oracle GoldenGate requires a database user account. Create this account and assign privileges according to the following guidelines.

• By default, the user who starts the Manager process becomes the default DB2 primary authorization ID for all of the Oracle GoldenGate processes that any users start in that Oracle GoldenGate instance. You can assign a different user to any process by means of JCL or UNIX variables.

• To monitor Oracle GoldenGate processing accurately, do not permit other applications or processes to operate as the Oracle GoldenGate user.

• Assign the DB2 privileges listed in Table 8-2 to the user by which Extract and Replicat will be running (default is the user who starts Manager). These are in addition to any permissions that DB2 ODBC requires. All Extract privileges apply to initial-load and log-based Extract processes, except where noted.

^Footnote 4

SELECT on source tables required only if tables contain LOB columns, or for an initial-load Extract, if used.

^Footnote 5

Required if using ADD CHECKPOINTTABLE in GGSCI to use the database checkpoint feature.

^Footnote 6

SQLEXEC enables stored procedures and queries to be executed by an Oracle GoldenGate process.