Dell PowerProtect DD Management Center (DDMC) 7.9 Installation and Administration Guide

Measuring physical capacity

Physical capacity measurement (PCM) provides space usage information for a subset of storage space for MTrees, Tenant Units, and Tenants.

PCM measures the physical capacity consumed by a subset of files within the file system, based on how the files in the subset deduplicate with other files in the subset. In other words, it measures the physical capacity that would be consumed on a Data Domain or PowerProtect system by a set of files, if that set of files were the only files on the system. This is a point in time measurement, based on when the measurement is requested.

You can specify the file system subset to measure in several ways: as an MTree, a Tenant Unit (all files within a Tenant Unit), or a Tenant (all files within a Tenant). Since a Tenant can span systems, in this case DDMC measures and reports the physical capacity consumed by the Tenant on each system.

The results of PCM jobs are retained for no more than one result per hour for the last 90 days, then no more than one per day for the last year, and then no more than one per week for the last 10 years.