The Direct Read & Write Rate graph keeps track of unbuffered I/O generated by the application¾that is, reads and writes that do not involve the buffer pool, but directly access the database to manage large amounts of data and to perform utility functions.
The graph contains the following series, which measure the direct read and write rates over consecutive monitoring intervals. These rates are based on the number of pages per second.
R ead—Plots the rate of direct reads generated by the application. Direct reads are used to read VARCHAR and LOB (large object) column data from disk and to perform backups.
Write —Plots the rate of direct writes generated by the application. Direct writes are used to write VARCHAR and LOB column data to disk and to perform data loads and restores.
The Statistics tab shows the direct read and write counts used to generate this graph. The names for these statistics begin with Direct. These statistics are derived from the DIRECT_READ and DIRECT_WRITE data elements that the DB2 snapshot monitor captures.