Apple Mac OS X Server manual Checking for Disk Problems, Labeling a Disk, Formatting a Disk

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After a partition has been created on a device, the partition needs to be formatted before the computer will be able to store data on the device. Formatting a disk partition creates the volume and sets the file system.

Labeling a Disk

Once a disk is formatted, it needs to be labeled. The disklabel tool manipulates “Apple Label” partition metadata. ”Apple Label” partitions allow for a disk device to have a consistent name, ownership, and permissions across reboots, even though it uses a dynamic pseudo file system for /dev.

The “Apple Label” partition uses a set of metadata (as a plist) in a reserved area of the partition. This metadata describes the owner, name, and so forth.

To create a disk label for a device with 1 MB of metadata area, owned by anne, with a device name of fred, and be writable by anne:

$ disklabel -create /dev/rdisk1s1 -msize=1M owner-uid=anne dev-devname=anne

name=anne owner-mode=0644

The following example prints out the key-value pairs from the previous example:

$ disklabel -properties /dev/rdisk1s1

See the disklabel man page for more information about creating disk labels.

Formatting a Disk

You can use newfs, located in /sbin, to create a new volume. newfs builds a file system on the specified special device, basing its defaults on the information in the disk label.

There are many parameters you can set when formatting disks, such as block and clump size, b-tree attribute, and catalog node sizes. Extreme care should be taken to ensure a successful format when modifying the settings beyond the default. Before running newfs, the disk must be labeled using the disklabel tool.

To fomat a disk:

$ newfs

See the newfs man page for options in detail.

To format a disk to HFS+, you would need to use the newfs_hfs tool located in /sbin:

$ newfs_hfs

See the newfs_hfs man page for more information.

Checking for Disk Problems

You can use the diskutil or fsck tool (fsck_hfs for HFS volumes) to check the physical condition and file system integrity of a volume. See the related man pages for more information.

Chapter 7 Working with Disks and Volumes