DB2 Server for VSE & VM: Performance Tuning Handbook

Ordering Data Lines

The database manager reads the storage pools specification file from the top down, reading each specification in sequence. It starts with every pool's specifications set to the default values, and updates the current settings with every line it encounters. For example, consider the following specification file:

-- Storage Pool Specification File 4-5 SEQ -- Line 1 1 DS2 -- Line 2 4 DS5 -- Line 3 2-3 BLK -- Line 4

As the database manager reads the file, pools 1 through 5 will all start with Data Spaces Support on, a working storage residency priority of 3, and striping on.

Line 1

Turns striping off for pools 4 and 5

Line 2

Sets the working storage residency priority for pool 1 to 2

Line 3

Sets the priority for pool 4 to 5.

Line 4

Turns Data Spaces Support off for pools 2 and 3.

You can also achieve the same results with the following specification file:

-- Storage Pool Specification File 1 DS2 STR 2 BLK STR 3 BLK STR 4 DS5 SEQ 5 DS3 SEQ

While both files are effectively the same, the second file defines each pool without relying on default values and is much easier to read and decipher.