Db2 Direct I/O Test

This test monitors the I/O activity on the currently active logical partitions.

Target of the test : A DB2 database server with DPF enabled

Agent deploying the test : An internal agent

Outputs of the test : One set of results for every logical partition of each database on the DB2 database server that is currently active

Configurable parameters for the test
  1. TEST PERIOD – How often should the test be executed
  2. Host – The IP address of the DB2 server
  3. Port – The port number through which the DB2 server communicates. The default port is 50000.
  4. user - Specify the name of the user who has any of the following privileges to the specified DATABASE: SYSADM or SYSCTRL or SYSMAINT or SYSMON. You can create a separate user on the OS hosting the DB2 server for this purpose, and assign any of the aforesaid privileges to that user. The steps for the same are detailed in the Creating a Special User for Monitoring DB2.
  5. password - Enter the password of the specified USER in the PASSWORD text box.
  6. confirm password – Confirm the password by retyping it here.
  7. database - Specify the name of the database on the monitored DB2 server to be used by this test
  8. SSL- If the target database server is SSL-enabled, then set the SSL flag to Yes. If not, then set the SSL flag to No.
Measurements made by the test
Measurement Description Measurement Unit Interpretation

Direct Read Rate:

Indicates the total number of direct reads by the application per second. In other words, it is the number of read operations that do not use the buffer pool.

Reads/Sec

Direct reads are performed in units, the smallest being a 512-byte sector. They are used when:

  • Reading LONG VARCHAR columns
  • Reading LOB (large object) columns
  • Performing a backup

A high value over a period of time may be indicative of a performance bottleneck.

 

Direct Write Rate:

Indicates the total number of direct writes by the application per second. In other words, it is the number of write operations that do not use the buffer pool.

Writes/Sec

Direct writes are performed in units, the smallest being a 512-byte sector. They are used when:

  • Writing LONG VARCHAR columns
  • Writing LOB (large object) columns
  • Performing a restore
  • Performing a load

A high value over a period of time may be indicative of a performance bottleneck.

Buffer Pool IO Rate:

Indicates the rate at which the buffer pool I/O operations are being done in this logical partition.

IOPS

In conjunction with the hit ratio statistics, and the characteristics of the applications executing, the I/O load may require adjustment of BUFFPAGE, or applications may require further tuning.