What is an inode?

Applies to

• ONTAP
• Inode

Answer

An inode in ONTAP is a pointer to any file or folder within the file system, including Snapshot copies.

• The number of files a volume can contain is determined by how many inodes it has.
• Inodes point to blocks that make up a file, and inodes also contain the metadata of the file.
• Volumes have both private and public inodes.
  • Public inodes are used for files that are visible to the user;
  • Private inodes are used for files that are used internally by ONTAP.
  • You can change only the maximum number of public inodes for a volume. You cannot affect the number of private inodes.
• Each inode uses 288 bytes of capacity
  • This means that having many inodes in a volume can also use up a non-trivial amount of physical space in addition to the capacity of the actual data as well.
  • If a file is less than 64 bytes, it is stored in the inode itself and does not use additional capacity.
• Each FlexVol volume has a finite number of inodes and has an absolute maximum of 2,040,109,451. 
• The space used by the Inode files counts against the 10% aggregate reserve in ONTAP.