Fragmentation is created when Essbase writes a data block to a new location on disk and leaves unused space in the former location of the data block. Block size increases because data from a data load or calculation is appended to the blocks; the blocks must therefore be written to the end of a data file.
The Essbase Kernel merges adjacent fragments into increasingly larger fragments so that unused space more likely will be reused.
In some cases, fragmentation cannot be reduced completely. Fragmentation is likely to occur in the following situations:
If you experience performance slowdowns, check to see if there is too much fragmentation of the database; if there is, you can take steps to reduce it.