EMC D-PDM-DY-23 - Dell PowerProtect Data Manager Deploy 2023 Exam

When protecting file systems, the " metadata density " —or thenumber of files—is the most significant factor affecting backup performance.

The Metadata Bottleneck:Every file in a backup requires a metadata look-up, an open/close operation, and cataloging. In environments with millions of small files, the overhead of processing these individual files often takes longer than the actual data transfer itself.

Slicing and Parallelism:To optimize performance, PPDM utilizes a " Slicer " (especially in Dynamic NAS protection). The slicer divides the file system into logical parts based on the file count and directory structure to allow multiple streams to run in parallel.

Optimization:While file system size (B) affects how much data is moved, the number of files (C) determines how many IOPS and CPU cycles the protection engine spends managing the file system walk. Therefore, understanding the file count is critical for properly sizing the number of protection engines needed to meet a backup window.