Db2 I/O Test

This test, executed by an internal agent, tracks various statistics pertaining to the inputs and outputs of a DB2 UDB database. The details of the test are provided below:

Target of the test : A DB2 database server

Agent deploying the test : An internal agent

Outputs of the test : One set of results for every database being monitored

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.
Measurements made by the test:
Measurement Description Measurement Unit Interpretation

Direct read rate:

Indicates the total number of direct reads by the application per sec. In other words, it 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 sec. 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 I/O rate:

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

IOs/Sec

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.