Mac OS X: Mac OS Extended format (HFS Plus) volume and file limits

  • Last Modified: July 29, 2008
  • Article: HT2422
  • Old Article: 25557

Summary

Learn the limits for files and volumes on disks that use the Mac OS Extended format (HFS Plus) in Mac OS X, including journaled HFS+ volumes.

Products Affected

Mac OS X Server, Mac OS X 10.4, Mac OS X 10.3, Mac OS X 10.2, Mac OS X 10.1, Mac OS X 10.0, Mac OS X 10.5

Volume and file limits in Mac OS X
Maximum number of volumes (all Mac OS X versions)
no limit
Maximum number of files (or files and folders) in a folder (all Mac OS X versions)
up to 2.1 billion (2)
Maximum volume size and file size (Mac OS X 10.0 - 10.1.5)
2 TB (1)
Maximum volume size and file size (Mac OS X 10.2 - 10.2.8)
8 TB (1)
Maximum volume size and file size (Mac OS X 10.3 - 10.3.9)
16 TB (1)
Maximum volume size and file size (Mac OS X 10.4 or later)
close to 8 EB (1,3)

Notes

  1. The theoretical maximum file size for a Mac OS Extended file system is millions of terabytes. In practice, the maximum file size is equivalent to the maximum volume size, except for a small amount of disk space reserved for file system information.
  2. Specifically, 2^31, or 2,147,483,648. However, the actual number of files that can be stored on a Mac OS Extended (HFS Plus) or journaled HFS+ volume depends on the volume's size and the size of the files. For example, a 160 GB Mac OS Extended volume with the default block size of 4 KB has 40 million available blocks. This volume could store up to 40 million very small files, but not 2 billion. A bigger disk with the same default block size could hold proportionately more files.
  3. 2^63 - 2^31 = 9,223,372,034,707,292,160, which is just under 8 exabytes (EB). One exabyte is roughly equivalent to one million terabytes.

For definitions of some of these terms see "Macintosh: File System Specifications & Terms".

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