The ProtecTIER Metadata Planner enables the field engineer to understand how many metadata file systems are required to support a repository of a certain size and the size of the metadata file systems. 

There are other utilities in the ProtecTIER Planner, such as upgrading from a previous version (with the import of historical user data), and customizing any disk performance information based on unique user scenarios when planning performance. 

For more information about capacity planning for a TS7650 Appliance environment, see IBM System Storage TS7600 with ProtecTIER Version 3.3 , SG24-7968. 

The ProtecTIER Planner should be used for capacity and performance planning while manually adapting it to a many-to-many environment at an early stage before the ProtecTIER deployment. The parameters to be considered are the same ones that are used in any replication deployment: 

GLYPH<SM590000> System workload. Both local backup and replication, including incoming and outgoing. 

GLYPH<SM590000> Network bandwidth. Available and required between the PT nodes on the grid. 

GLYPH<SM590000> Time frames. Backup and replication windows or concurrent operation. 

## 7.2 Dependencies from a back-end storage subsystem view 

Independent from the back-end storage subsystem, some general guidelines indicate how to lay out your storage for optimal usage of ProtecTIER. 

Depending on whether you plan to deploy a small or large ProtecTIER gateway solution, be aware of certain limits and effects. 

All storage subsystems come with multiple controllers. So, you must use at least two LUNs to distribute them across both controllers of a storage subsystem. 

All IBM Storage Subsystems are based on standard hardware. For example, the IBM System Storage DS8000fi is based on the IBM System p architecture, and the IBM Storwizefi Family and SAN Volume Controller are based on the IBM System x architecture. With these architectures, the controller nodes of the storage subsystems tend to have multiple processors driving the input/output (I/O), and multiple cores per processor. 

To use all of these resources, you must have multiple LUNs per controller at the same time. For example, with the IBM Storwize Family and SAN Volume Controller, you must have at least four arrays per controller to ensure the optimal usage of all computing cores. 

Based on these calculations, assume that a minimum number of eight LUNs enables an optimal usage of the available resources. These are some more general assumptions. Your individual system might be fine with fewer than eight LUNs if sizing and planning were done for your individual requirements. 

## 7.3 Dependencies from a ProtecTIER view 

ProtecTIER uses a special method to write data to disk. ProtecTIER writes data to disk by creating data in or appending data to the repository structure. These are the two principal modes of operation. Data that can be expired from a ProtecTIER perspective is not overwritten. It is deleted by the maintenance processes and is reshaped by the defragger practices before it is used again by write or append operations. 

