The amount of memory that is required for Oracle GoldenGate depends on the number of concurrent processes that will be running. At minimum on the source system, there is a primary Extract process that captures source data and a secondary Extract data-pump process that transfers data across the network. At minimum on the target system is at least one Replicat process that applies the replicated data to the target database. In some cases, these processes might all operate on the same system, depending on the required configuration.
- The Oracle GoldenGate GGSCI command interface fully supports up to 5,000 concurrent Extract and Replicat processes per instance of Oracle GoldenGate. An instance of Oracle GoldenGate equates to one Manager process, which is the main controller process.
- Each Extract and Replicat process needs approximately 25-55 MB of memory, or more depending on the size of the transactions and the number of concurrent transactions.
- Allocating and managing active buffers efficiently.
- Recycling old buffers instead of paging to disk, when possible.
- Paging less-used information to disk, when necessary.
The cache manager keeps an Oracle GoldenGate process working within the soft limit of its global cache size, only allocating virtual memory (not physical memory) on demand. System calls to increase the cache size are made only as a last resort and, when used, are always followed by the release of virtual memory back to the system. The system must have sufficient swap space for each Oracle GoldenGate Extract and Replicat process that will be running. To determine the required swap space:
- Start up one Extract or Replicat.
- Run GGSCI.
- View the report file and find the line PROCESS VM AVAIL FROM OS (min).
- Round up the value to the next full gigabyte if needed. For example, round up 1.76GB to 2 GB.
- Multiply that value by the number of Extract and Replicat processes that will be running. The result is the maximum amount of swap space that could be required.
Disk requirements
Assign the following free disk space:
- 50-150 MB, depending on the database and platform. This includes space for the compressed download file and space for the uncompressed files. You can delete the download file after the installation is complete.
- 40 MB for the working directories and binaries for each instance of Oracle GoldenGate that you are installing on the system. For example, to install two builds of Oracle GoldenGate into two separate directories, allocate 80 MB of space.
- To install Oracle GoldenGate into a cluster environment, install the Oracle GoldenGate binaries and files as the Oracle user on a shared file system that is available to all cluster nodes. See “Preparing to install Oracle GoldenGate within a cluster” on page 28 for more information.
- 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. Start with 1 GB and adjust as needed. See also the following guidelines.
To prevent trail activity from interfering with business applications, assign a separate disk or file system to contain the trail files. These files are created during processing to store all of the data that is captured by Oracle GoldenGate. The default size is 10 megabytes, but can be changed during the configuration process. Trail files accumulate but can be purged according to rules set with the PURGEOLDEXTRACTS parameter.
Trail files can reside on drives that are local to the Oracle GoldenGate installation, or they can reside on NAS or SAN devices. In an Oracle cluster, they can reside on ASM or DBFS storage. You decide and specify the location of the trails when you configure Oracle GoldenGate.
For trails that are stored at the source location, there should be enough space to handle data accumulation should the network connection fail. In a typical configuration, a secondary Extract process (known as a data pump) sends data from a local trail over the network, and it will fail when the network does. However, the primary Extract that reads the transaction logs and writes to the local trail will continue to do so. This Extract should not be stopped during a failure; otherwise, transaction data might be missed if the transaction logs recycle or get removed from the system before the data is completely captured. There must be enough disk space to hold the data accumulation, or Extract will abend.
For trails at the target location, provide enough disk space to handle data accumulation according to the purge rules set with the PURGEOLDEXTRACTS parameter. Even with PURGEOLDEXTRACTS in use, data will always accumulate on the target because it is transferred across the network faster than it can be applied to the target database.
To estimate required trail space
- Estimate the longest time that the network could be unavailable. Plan to store enough data to withstand the longest possible outage, because otherwise you will need to resynchronize the source and target data if the outage outlasts disk capacity.
- Estimate how much transaction log volume your business applications generate in one hour.
- Use the following formula to calculate the required disk space.
This equation uses a multiplier of 40 percent because only about 40 percent of the data in a transaction log is needed by Oracle GoldenGate.
NOTE This formula is a conservative estimate, and you should run tests once you have configured Oracle GoldenGate to determine exactly how much space you need.
Temporary disk requirements
By default, Oracle GoldenGate maintains data that it swaps to disk in the dirtmp subdirectory 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 to this directory with the CACHEDIRECTORY option of the CACHEMGR parameter.
Network
- For optimal performance and reliability, especially in maintaining low latency on the target, use the fastest network possible and install redundancies at all points of failure.
- Configure the system to use TCP/IP services, including DNS. Oracle GoldenGate supports IPv4 and IPv6 and can operate in a system that supports one or both of these protocols.
- Configure the network with the host names or IP addresses of all systems that will be hosting Oracle GoldenGate processes and to which Oracle GoldenGate will be connecting. Host names are easier to use.
- Oracle GoldenGate requires some unreserved and unrestricted TCP/IP ports, the number of which depends on the number and types of processes in your configuration. See the Oracle GoldenGate Windows and UNIX Administrator’s Guide for details on how to configure the Manager process to handle the required ports.
- Keep a record of the ports that you assigned to Oracle GoldenGate. You will specify them with parameters when configuring the Manager process.
- Configure your firewalls to accept connections through the Oracle GoldenGate ports.
Operating system privileges
- To install on Windows, the person who installs Oracle GoldenGate must log in as Administrator.
- To install on UNIX, the person who installs Oracle GoldenGate must have read and write privileges on the Oracle GoldenGate installation directory.
- The Oracle GoldenGate Extract, Replicat, and Manager processes must operate as an operating system user that has privileges to read, write, and delete files and subdirectories in the Oracle GoldenGate directory. In addition, the Manager process requires privileges to control the other Oracle GoldenGate processes.
- (Classic capture mode) In classic capture mode, the Extract process reads the redo logs directly and must operate as an operating system user that has read access to the log files, both online and archived. On UNIX systems, that user must be a member of the group that owns the Oracle instance. If you install the Manager process as a Windows service during the installation steps in this documentation, you must install as Administrator for the correct permissions to be assigned. If you cannot install Manager as a service, assign read access to the Extract process manually, and then always run Manager and Extract as Administrator.
- Dedicate the Extract, Replicat, and Manager operating system users to Oracle GoldenGate. Sensitive information might be available to anyone who runs an Oracle GoldenGate process, depending on how database authentication is configured.
Itanium requirements
To install Oracle GoldenGate on a Microsoft Itanium system, the vcredist_IA64.exe runtime library package must be installed. You can download this package from the Microsoft website. This package includes VisualStudio DLLs necessary for Oracle GoldenGate to operate on the Itanium platform. If these libraries are not installed, Oracle GoldenGate generates the following error.
The application failed to initialize properly (0xc0150002). Click on Ok to terminate the application.
Other programs
- Before installing Oracle GoldenGate on a Windows system, install and configure the Microsoft Visual C ++ 2005 SP1 Redistributable Package. Make certain it is the SP1 version of this package, and make certain to get the correct bit version for your server. This package installs runtime components of Visual C++ Libraries.
- Oracle GoldenGate fully supports virtual machine environments created with any virtualization software on any platform. When installing Oracle GoldenGate into a virtual machine environment, select a build that matches the database and the operating system of the virtual machine, not the host system. For example, on a Windows system with a RHAS 4.0 virtual machine running Oracle11g, you would install the RHAS 4.0 build for Oracle 11g, just as you would on an actual Linux machine.
Installation on UNIX, Linux, or z/OS
- Download Golden Gate 11g
- create Golden Gate home
$ tar -xvof
$ ggsci
GGSCI> create subdirs
Installation on Windows
- Download Golden Gate 11g
- create Golden Gate home
C:\ORACLE_BASE\product\goldengate11g> unzip the golden gate
C:\ ORACLE_BASE\product\goldengate11g> INSTALL ADDSERVICE ADDEVENTS
C:\ ORACLE_BASE\product\goldengate11g> ggsci
GGSCI> create subdir
Golden Gate install and working directories created... good to go..
