The first and most powerful setting is the “Only Compact when Freespace exceeds” fields on the Optimization Schedule.
By setting this field a database can only become a candidate for DBMT compacting when the freespace within it exceed the amount specified. This avoids potentially processing hundreds of database where little, or no, freespace can be recovered. This dramatically reduces DBMT processing times, prevents fragmenting those databases, and prevents unnecessary DBIID changes, which also reduces backup requirements.
Here is an example where only 12 databases exceed the Freespace exceeds setting:
As a result when DBMT runs all other databases are excluded from the compact sub-task of DBMT
DBMT therefore only compacts 12 of the 280+ databases
You can further fine-tune the databases that are excluded from compact processing by adding them to the “Exclude the following databases from DBMT processing field” or adding the directory to the “Exclude the following directories from DBMT processing field”
The end result is significantly less time “compacting for the sake of compacting” and the benefits from there are substantial.
One final note, the DBMT optimizations discussed here are only available in DDO.
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