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QUERY OCCUPANCY: difference between physical and logical space

Question & Answer


Question

What is the difference between the physical and logical space values reported in the QUERY OCCUPANCY output?

Cause

When a backup or archive is performed from a client node, the Tivoli Storage Manager server may group multiple client files into an aggregate object, which represents the individual files. The size of the aggregate depends on the sizes of the client files being stored, and the number of bytes and files allowed for a single transaction. Inevitably, over a period of time some of the files within an aggregate will be expired or deleted, creating empty space within the aggregate.

Answer

The physical space reported in the QUERY OCCUPANCY output reflects the total amount of space occupied by the aggregates, including any empty space within the aggregates. The logical space value reflects only the amount of occupied space by the remaining, valid files within the aggregates. Any empty space within an aggregate created as a result of files having been expired/deleted is not reflected in the logical space value.

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Product Synonym

TSM

Document Information

Modified date:
17 June 2018

UID

swg21636493