DSM/Tape Catalog User's Guide

Database Design of DSM/TC

DSM/Tape Catalog User’s Guide — 520233-008

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Sizing Estimate for the DSM/TC Database

Because SQL/MP automatically uses disk space compression when writing information

in a database, the values in this estimate are greater than the actual space needed.

The values are based on these assumptions:



The average tape file name length is 20 characters.



The average volume catalog name length is 18 characters.



The average file catalog name length is 18 characters.



The average pool name length is 10 characters.



The average volume name length is 6 characters.



The average disk file name length is 26 characters.

The only other space requirement is that each subvolume with a file catalog or volume

catalog also have an SQL catalog that is created automatically. The disk space

required for the SQL catalog is minimal and does not change with an increase in size

of the file or volume catalog.

Minimum Maximum Average

Each tape file recorded 140 bytes 540 bytes 270 bytes

Each disk file recorded 180 bytes 600 bytes 410 bytes

Each pool configured 35 bytes 80 bytes 50 bytes

Each volume in a pool 80 bytes 340 bytes 180 bytes

Each assigned volume set 12 bytes 70 bytes 40 bytes