- Large Depot slots
- Small Depot slots
The Large Depot slots are used by aging routines to write multiple blocks to the Depot area with a single I/O.
The Small Depot slots are used when individual blocks that require Depot protection are written to the Depot area by foreground tasks.
The number of cylinders allocated to the Depot area is fixed at startup. Contact Teradata Support if you want to change this value.
The number of Depot area cylinders allocated is per pdisk, so their total number depends on the number of pdisks in your system. Sets of pdisks belong to a subpool, and the system assigns individual AMPs to those subpools.
The system does not assign pdisks to AMPs, so the system calculates the average number of pdisks per AMP in the subpool from the vconfig GDO when allocating Depot cylinders, rounding up the calculated value if necessary. The system then multiplies the result by the specified values to get the total number of depot cylinders for each AMP. Using this method, the system assigns each AMP the same number of Depot cylinders.
The concept is to disperse the Depot cylinders evenly across the system. This prevents one pdisk from becoming overwhelmed by all the Depot writes for your system.