Q5.7:
What is the architectural limit of the number of files in a file system?
A5.7:
The architectural limit of the number of files in a file system is determined by the file system format:
For file system created with GPFS V3.4 or later, the architectural limit is 2∧64.
The current tested limit is 9,000,000,000.

For file systems created with GPFS V2.3 or later, the limit is 2,147,483,648.
For file systems created prior to GPFS V2.3, the limit is 268,435,456.
Please note that the effective limit on the number of files in a file system is usually lower than the architectural limit, and could be adjusted using the mmchfs command (GPFS V3.4 and later use the --inode-limit option).

The maximum number of files that can be created can be specified by using the --inode-limit option on the mmchfs command. Allowable values, which range from the current number of created inodes (determined by issuing the mmdf command with the -F option) through the maximum number of files that are supported, are constrained by the formula:


maximum number of files = (total file system space) / (inode size + subblock size)


You can determine the inode size (-i) and subblock size (value of the -B parameter / 32) of a file system by running the mmlsfs command. The maximum number of files in a file system may be specified at file system creation by using the --inode-limit option on the mmcrfs command, or it may be increased at a later time by using --inode-limit on the mmchfs command. This value defaults to the size of the file system at creation divided by 1 MB and cannot exceed the architectural limit. When a file system is created, 4084 inodes are used by default; these inodes are used by GPFS? for internal system files.