System Administration Guide: Basic Administration

Number of Files

The number of inodes parameter determines the number of files you can have in the file system: one inode for each file. The number of bytes per inode determines the total number of inodes that are created when the file system is made: the total size of the file system divided by the number of bytes per inode. Once the inodes are allocated, you cannot change the number without re-creating the file system.

The default number of bytes per inode is 2048 bytes (2 Kbytes) if the file system is less than one Gbyte. If the file system is larger than one Gbyte, the following formula is used:

File System Size 

Number of Bytes Per Inode 

Less than or equal to 1 Gbyte 

2048 

Less than 2 Gbytes 

4096 

Less than 3 Gbytes 

6144 

3 Gbytes or greater 

8192 

If you have a file system with many symbolic links, they can lower the average file size. If your file system is going to have many small files, you can give this parameter a lower value. Note, however, that having too many inodes is much better than running out of inodes. If you have too few inodes, you could reach the maximum number of files on a disk slice that is practically empty.