I’m setting up a new external hard drive to connect to a media server and I need to decide which filesystem to format the drive to. It doesn’t matter which format a hard drive is formatted to from the factory (FAT32 for me on this occasion), the option exists to wipe the drive and use a different format right inside OS X. Formatting can be done with the Mac OS X Disk Utility, found in the /Applications/Utilities folder. Here are the formatting options with advantages/disadvantages listed:

FAT32 (File Allocation Table)

• Read/Write FAT32 from both native Windows and native Mac OS X
• Maximum file size: 4GB
• Maximum volume size: 2TB
• You can use this format if you share the drive between Mac OS X and Windows computers and have no files larger than 4GB

NTFS (Windows NT File System)

• Read/Write NTFS from native Windows
• Read only NTFS from native Mac OS X
• To Read/Write/Format NTFS from Mac OS X, here are some alternatives:
• For Mac OS X 10.4 or later (32 or 64-bit), install Paragon (approx $20) (Best Choice for Lion)
• For 32-bit Mac OS X, install NTFS-3G for Mac OS X (free) (does not work in 64-bit mode)
• For 64-bit Snow Leopard, read this: MacFUSE for 64-bit Snow Leopard.
• For 64-bit Lion, see this: OSXFuse.
• Some have reported problems using Tuxera (approx $36)
• Native NTFS support can be enabled in Snow Leopard and Lion, but is not advisable, due to instability.
• AirPort Extreme (802.11n) and Time Capsule do not support NTFS
• Maximum file size: 16 TB
• Maximum volume size: 256TB
• You can use this format if you routinely share a drive with multiple Windows systems.

HFS+ (Hierarchical File System, a.k.a. Mac OS Extended (Journaled) Don’t use case-sensitive)

• Read/Write HFS+ from native Mac OS X
• Required for Time Machine or Carbon Copy Cloner or SuperDuper! backups of Mac internal hard drive
• To Read/Write HFS+ from Windows, Install MacDrive
• To Read HFS+ (but not Write) from Windows, Install HFSExplorer
• Maximum file size: 8EiB
• Maximum volume size: 8EiB
• You can use this format if you only use the drive with Mac OS X, or use it for backups of your Mac OS X internal drive, or if you only share it with one Windows PC (with MacDrive installed on the PC)

exFAT (FAT64)

• Supported in Mac OS X only in 10.6.5 or later
• Not all Windows versions support exFAT. See disadvantages
• exFAT (Extended File Allocation Table)
• AirPort Extreme (802.11n) and Time Capsule do not support exFAT
• Maximum file size: 16 EiB
• Maximum volume size: 64 ZiB
• You can use this format if it is supported by all computers with which you intend to share the drive

My Decision

I’m running OS X Lion 10.7 at the time of writing. I’m using a Netgear DGND3300v2 Router with Readyshare for my home network. Readyshare supports FAT16, FAT32, NTFS and Linux filesystems EXT3 AND EXT3. My external drive is 2 terabytes. FAT32 will probably suffice as I don’t expect to store media files larger than 4gb on the drive in the forseeable future. But I’m going to play it safe and choose the NTFS option, installing OSXFuse to do the formatting and initial file copying.