Apple Mac OS X Server manual Displaying Disk Information, Monitoring Disk Space

Displaying Disk Information

The df tool located in /bin is designed to display free disk space. In addition, df is a useful way to find out what your current disk partitions are, how much space each one takes up, which block each partition starts on, which device file is associated with each partition, and where each partition is mounted.

To display disk information:

$ df

The computer will respond with output similar to the following:

Filesystem	512-blocks	Used	Avail Capacity		Mounted on
/dev/disk0s3	156039264	26138984	129388280	17%	/
devfs	193	193	0	100%	/dev
fdesc	2	2	0	100%	/dev
<volfs>	1024	1024	0	100%	/.vol
automount -nsl [170]	0	0	0	100%	/Network
automount -fstab [174]	0	0	0	100%	/automount/
Servers
automount -static [174]	0	0	0	100%	/automount/
static

The -loption restricts reporting to local drives only. The -koption displays sizes in kilobyte format.

Each line in the output refers to a different partition. The first column tells you the device file associated with that partition. The second column displays the capacity of the partition followed by used and available space on the volume. The last column tells you where the partition is mounted.

Monitoring Disk Space

You can monitor the amount of free space on disks and take predefined actions when thresholds are exceeded. When you need more vigilant monitoring of disk space than the log rolling scripts provide, you can use the diskspacemonitor tool. It lets you monitor disk space and take action more frequently than once a day when disk space is critically low, and gives you the opportunity to provide your own action scripts. diskspacemonitor is disabled by default.

To enable diskspacemonitor:

$ sudo diskspacemonitor on.

You may be prompted for your password. See the diskspacemonitor man page for more information.

Chapter 7 Working with Disks and Volumes

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