Metadata units calculation

Content Software for File User Guide

Version

4.2.x

Audience

anonymous

Part Number

MK-HCSF000-03

Every metadata unit within the Content Software for File system demands 4 KB of SSD space (excluding tiered storage) and occupies 20 bytes of RAM.

Throughout this documentation, the restriction on metadata per filesystem is denoted as the max-files parameter. This parameter includes the files' count and respective sizes.

The following table outlines the requisite metadata units based on file size. These specifications apply to files stored on SSDs or tiered to object stores.

File size	Number of metadata units	Example
< 0.5 MB	1	A filesystem with 1 billion files of 64 KB each requires 1 billion metadata units.
0.5 MB - 1 MB	2	A filesystem with 1 billion files of 750 KB each, requires 2 billion metadata units.
> 1 MB	2 for the first 1 MB plus 1 per MB for the rest MBs	A filesystem containing 1 million files, each sized at 129 MB, requires 130 million metadata units. This calculation includes 2 units for the first 1 MB and an additional unit per MB for the subsequent 128 MB. A filesystem containing 10 million files, each sized at 1.5 MB, requires 30 million metadata units. A filesystem containing 10 million files, each sized at 3 MB, requires 40 million metadata units.

Note: Each directory requires two metadata units instead of one for a small file.