System Administration Guide: Devices and File Systems

Number of Inodes (Files)

The number of bytes per inode specifies the density of inodes in the file system. The number is divided into the total size of the file system to determine the number of inodes to create. 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 KB) if the file system is less than 1 GB. If the file system is larger than 1 GB, the following formula is used:

File System Size 

Number of Bytes Per Inode 

Less than or equal to 1 GB 


Less than 2 GB 


Less than 3 GB 


3 GB up to 1 TB 


Greater than 1 TB or created with -T option


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.