IBM License Metric Tool Version 9.0 (includes version 9.0.1, and ) Tuning Performance Guide

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1 IBM License Metric Tool Version 9.0 (includes version 9.0.1, and ) Tuning Performance Guide

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3 IBM License Metric Tool Version 9.0 (includes version 9.0.1, and ) Tuning Performance Guide

4 Tuning Performance Guide This edition applies to IBM License Metric Tool version (product number 5724-T40) and to all subsequent releases and modifications until otherwise indicated in new editions. Copyright IBM Corporation 2002, US Government Users Restricted Rights Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp.

5 Tuning performance You can use the information in this section to identify and resolve the primary system bottlenecks in your environment. The tips and performance recommendations can be used both in big data environments and in smaller environments that are running on low-performance hardware. Infrastructure The main factor that affects the performance of the License Metric Tool server is the performance of the underlying infrastructure on which the application server and the DB2 database are running. You must ensure that the recommended requirements are met. Important: The official hardware recommendations were prepared with assumption that the License Metric Tool server is running on a dedicated physical server or servers. If virtual machines are used, the specified hardware (processor, RAM, or disk space) must be exclusively dedicated to those virtual machines not shared with any others. Even if you meet the recommended requirements, the application might work slowly because of issues with the underlying hardware. The issues might be caused by, for example, sharing resources with other machines within the virtual environment. You can run some diagnostic methods to ensure that the underlying infrastructure is in good shape. Memory performance RAM performance metrics such as seek time or memory bandwidth, are strictly dependent on the memory type, which is linked with the processor type. Restriction: Do not run your server on a virtual machine for which memory compression was enabled, for example in x86 virtualization that is provided by VMware. It is especially true in case of the computer on which the DB2 database is running. Pay particular attention to the amount of memory that is available for License Metric Tool and the DB2 application. It is important to monitor the RAM usage on a daily basis because memory usage differs greatly depending on how the application is being used. The main factors besides the environment size include: v The number of concurrent web UI users v The frequency of data imports Memory monitoring is especially important on the database computer as insufficient amount of RAM can significantly slow down background tasks, such as PVU data aggregation because of memory swapping. Swapping, also known as paging, is the use of secondary disk storage to store and retrieve application data for use in RAM. It is automatically performed by the operating system and typically occurs when the available RAM is depleted. Swapping can have a Copyright IBM Corporation 2002, 2013 IBM 2002,

6 significant impact on DB2 performance and should be avoided. To avoid swapping, ensure that sufficient RAM is available on the computer so processes do not consume all the available RAM. Use the following Linux tools to monitor RAM usage and memory swapping: v top v free v vmstat v or sar If you notice that there is almost no free memory available to License Metric Tool and the DB2 processes are being swapped to disk, the best solution is to increase the RAM memory size. Storage performance To ensure good performance of License Metric Tool, it is essential to have good storage performance on the database server computer. The storage performance of the License Metric Tool server alone is not that important. The recommended average disk speed for the database server computer is specified in the following table. Table 1. Recommended average disk speed for the database server computer in specific environments Deployment Size Small (up to 5000 endpoints) Medium ( endpoints) Large (more than endpoints) Disk Speed 100 MB/sec 250 MB/sec 400 MB/sec Running hard disk tests On Linux, you can use the hdparm and dd commands or the Bonnie++ application to determine the hard disk write rate. You can also use the iostat command to determine average disk usage. Determining the write rate with the hdparm command: In the Linux operating system, there is a built-in hdparm command that can be used to determine the hard disk write rate. Procedure In the Linux console, enter hdparm -t path_to_the_test_file hdparm -t /dev/sda1 Timing buffered disk reads: 200 MB in 1.19 seconds = MB/sec Running the disk test with the DD application: About this task The DD test measures the most basic single-threaded disk access: a large sequential write, followed by a large sequential read. It is relevant for the database performance testing effort because it gives you the maximum speed for sequential scans for large tables. 2 IBM License Metric Tool: Tuning Performance Guide

7 Note: Check the RAM size on the testing computer to correctly run a DD test and avoid file system caching that can distort the test results. Procedure 1. Create a file that is twice the size of the RAM capacity on the test computer and copy it to the target computer hard disk. In your tests use a4kbblock size because the default page size of the DB2 table space that License Metric Tool is using is 4 KB. For example, if you have 16 GB of RAM, run the following command so that a 32 GB file named ddfile is created in the current directory: time sh -c "dd if=/dev/zero of=ddfile bs=4k count= && sync". Note: Some implementations of DD report the write rate, but the time command always returns the execution time that is larger than the DD time. The time and rate reported by DD represent the rate without any lag or synchronization time. Divide the data size by the time reported by the time command to get the real synchronous file writing rate. Example: records in records out bytes (32 GB) copied, s, 842 MB/s real 3m49.192s user 0m0.450s sys 0m38.282s In this example, the rate for writes including caching is 842 MB/s, but including the synchronization time it is much poorer only about MB/s (32 GB / 3 minutes 49 seconds). 2. To flush out the file system cache so that you read directly from the disk later, write to the disk another large file: dd if=/dev/zero of=ddfile2 bs=4k count= Read the first large file. Since the file system cache is filled with the second file, this test returns a valid read rate result: time dd if=ddfile of=/dev/null bs=4k records in records out bytes (32 GB) copied, seconds, MB/s real 3m6.496s user 0m1.652s sys 0m10.753s 4. Compare the results with those in the table Recommended average disk write and read rates for the database server computer to determine whether your storage can handle the DB2 database for your environment. The system should easily be able to deal with a database of up to clients. Determining disk usage: If response times are slow, check the average disk usage with the iostat command. Disk usage times of greater than 80% can reduce I/O performance, it is desirable to have average disk usage below 40%. Procedure In the Linux console, enter iostat -x interval duration Where: Tuning performance 3

8 v interval Is the time interval in seconds. If no interval is specified, the output reflects the values over the entire period since the system was rebooted v duration Is the number of times to run the command Example: iostat -x 30 5 Tuning performance in big data environments You can learn the possible causes of the most common performance issues in big data environments and known solutions to these issues, together with several general tips that help you to keep the system in good shape and avoid performance problems. Database maintenance See the topic Maintaining the database to learn more how to manually maintain the database tables. It is also possible to maintain the tables automatically by using the built-in DB2 mechanisms. Scalability of multiple concurrent UI users Concurrent users can work on the License Metric Tool web UI, but their number is limited for performance reasons. The application should be able to handle performance load from two concurrent web UI users when it is running on the hardware that meets the minimal hardware requirements. To be able to handle more than two concurrent web UI users, the underlying hardware must meet the recommended hardware requirements. Configuring the transaction logs size If your environment consists of many endpoints, increase the transaction logs size to improve performance. About this task The transaction logs size can be configured through the LOGFILSIZ DB2 parameter that defines the size of a single log file. To calculate the value that can be used for this parameter, you must first calculate the total disk space that is required for transaction logs in your specific environment and then divide it, thus obtaining the size of one transaction log. The required amount of disk space depends on the number of endpoints in your environment and the number of endpoints for which new scan results are available and processed during the data import. Important: Use the provided formula to calculate the size of transaction logs that are generated during the import of data. More space might be required for transaction logs that are generated when you remove the data source. Procedure 1. Use the following formula to calculate the disk space for your transaction logs: <The number of endpoints> x1mb+<the number of endpoints for which new scan results are imported> x1mb+1gb 2. Divide the result by to obtain the size of a single transaction log file. 3. Run the following command to update the transaction log size in your database. Substitute value with the size of a single transaction log. 4 IBM License Metric Tool: Tuning Performance Guide UPDATE DATABASE CONFIGURATION FOR SUADB USING LOGFILSIZ value

9 4. For the changes to take effect, restart the database. Run the following commands: DEACTIVATE DB SUADB DB2START DB2STOP ACTIVATE DB SUADB 5. Restart the License Metric Tool server. a. To stop the server, run the following command: /etc/init.d/suaserver start b. To start the server, run the following command: Example v /etc/init.d/suaserver stop Calculating the single transaction log size for endpoints and scan results: x1MB+15000x1MB+1GB=114 GB 114 / = Increasing Java heap size The default settings for the Java heap size might not be sufficient for medium and large environments. If your environment consists of more than 5000 endpoints, increase the memory available to Java client processes by increasing the Java heap size. Procedure 1. Go to the <INSTALL_DIR>/wlp/usr/servers/server1/ directory and edit the jvm.options file. 2. Set the maximum Java heap size (Xmx) to one of the following values, depending on the size of your environment: v For medium environments ( endpoints), set the heap size to 6144m. v For large environments (over endpoints), set the heap size to 8192m. 3. Restart the License Metric Tool server. Maintaining the database To ensure that the DB2 database works properly, you need to regularly back up your data and perform maintenance actions. About this task The configuration of DB2 has a significant impact on performance. You should perform some standard actions to administer the database correctly. If you have DB2 administration professionals, they can monitor the DB2 health and performance. In other cases, you should follow the procedures that are described in this topic to keep your database healthy. Procedure 1. Perform regular backups of the data that is stored in the database. It is advisable to back up the database before updating the software catalog or upgrading the server to facilitate recovery in case of failure. a. Stop the server. Tuning performance 5

10 b. In the DB2 command-line interface, run the following command: db2 backup database SUADB. c. Start the server The backup is created in the current working directory, and the file name contains the instance name and time stamp of the backup procedure (for example: TLMA.0.db2inst1.NODE0000.CATN ). For more information about database backup strategies, see DB2 topic: Developing a backup and recovery strategy. 2. Reorganize the table to match the index and to reclaim space: a. Stop the License Metric Tool server. b. In the DB2 command-line interface, run the following commands: v db2 connect to SUADB v db2 -x "select reorg table,substr(rtrim(tabschema). rtrim(tabname),1,50), allow no access; from syscat.tables where type = T and tabschema in ( ADM,SAM, DBO ) order by tabschema,tabname " > reorgs.sql v db2 -tvf reorgs.sql v db2 terminate c. Start the License Metric Tool server. 3. Keep the statistics up-to-date. By default, DB2 statistics are run automatically. If this option is disabled, you must manually run the following commands: a. Stop the License Metric Tool server. b. In the DB2 command-line interface, run the following commands: v db2 connect to SUADB v db2 -x "select runstats on table,substr(rtrim(tabschema). rtrim(tabname),1,50), and indexes all; from syscat.tables where type = T and tabschema in ( DBO, SAM, ADM ) order by tabschema,tabname " > runstats.sql v db2 -tvf runstats.sql v db2 terminate c. Start the server. What to do next For a more advanced investigation of queries that are used by the License Metric Tool server, you should use the DB2 design advisor command (db2advis). It helps in finding new indexes that can improve the database performance. The Design Advisor uses the output from the DB2 monitors to suggest the creation of new indexes. The suggestions are based on the queries that are found in monitors. For more information about Design Advisor, consult the DB2 documentation: v DB db2advis - DB2 Design Advisor command DB2 topic: Design Advisor v DB db2advis - DB2 Design Advisor command DB2 topic: Design Advisor 6 IBM License Metric Tool: Tuning Performance Guide

11 Notices This information was developed for products and services offered in the U.S.A. IBM may not offer the products, services, or features discussed in this document in other countries. Consult your local IBM representative for information on the products and services currently available in your area. Any reference to an IBM product, program, or service is not intended to state or imply that only that IBM product, program, or service may be used. Any functionally equivalent product, program, or service that does not infringe any IBM intellectual property right may be used instead. However, it is the user's responsibility to evaluate and verify the operation of any non-ibm product, program, or service. IBM may have patents or pending patent applications covering subject matter described in this document. The furnishing of this document does not grant you any license to these patents. You can send license inquiries, in writing, to: IBM Director of Licensing IBM Corporation North Castle Drive Armonk, NY U.S.A. For license inquiries regarding double-byte character set (DBCS) information, contact the IBM Intellectual Property Department in your country or send inquiries, in writing, to: Intellectual Property Licensing Legal and Intellectual Property Law IBM Japan, Ltd , Nihonbashi-Hakozakicho, Chuo-ku Tokyo , Japan The following paragraph does not apply to the United Kingdom or any other country where such provisions are inconsistent with local law: INTERNATIONAL BUSINESS MACHINES CORPORATION PROVIDES THIS PUBLICATION AS IS WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Some states do not allow disclaimer of express or implied warranties in certain transactions, therefore, this statement may not apply to you. This information could include technical inaccuracies or typographical errors. Changes are periodically made to the information herein; these changes will be incorporated in new editions of the publication. IBM may make improvements and/or changes in the product(s) and/or the program(s) described in this publication at any time without notice. Any references in this information to non-ibm Web sites are provided for convenience only and do not in any manner serve as an endorsement of those Web sites. The materials at those Web sites are not part of the materials for this IBM product and use of those Web sites is at your own risk. Copyright IBM Corp. 2002,

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