Managing available space on new disks

Displaying free disk space

You use the df command to display the amount of free disk space in the specified volume or aggregate or all volumes and aggregates (shown as Filesystem in the command output) on the storage system. This command displays the size in 1,024-byte blocks, unless you specify another value, using one of the following options: -h (causes Data ONTAP to scale to the appropriate size), -k (kilobytes), -m (megabytes), -g (gigabytes), or -t (terabytes).

On a separate line, the df command also displays statistics about how much space is consumed by the snapshots for each volume or aggregate. Blocks that are referenced by both the active file system and by one or more snapshots are counted only in the active file system, not in the snapshot line.

Disk space report discrepancies

The total amount of disk space shown in the df output is less than the sum of available space on all disks installed in an aggregate.

In the following example, the df command is issued on a traditional volume with three 72-GB disks installed, with RAID-DP enabled, and the following data is displayed:

When you add the numbers in the kbytes column, the sum is significantly less than the total disk space installed. The following behavior accounts for the discrepancy:

The two parity disks, which are 72-GB disks in this example, are not reflected in the output of the df command.
The storage system reserves 10 percent of the total disk space for efficiency, which df does not count as part of the file system space.
Note
The second line of output indicates how much space is allocated to snapshots. Snapshot reserve, if activated, can also cause discrepancies in the disk space report. For more information, see the Data Protection Online Backup and Recovery Guide.

Displaying the number of hot spare disks with the Data ONTAP CLI

To ascertain how many hot spare disks you have on your storage system using the Data ONTAP CLI, complete the following step.

Step	Action
1	Enter the following command: aggr status -s Result If there are hot spare disks, a display like the following appears, with a line for each spare disk, grouped by checksum type: Pool1 spare disks RAID Disk Device HA SHELF BAY CHAN Pool Type RPM Used (MB/blks) Phys(MB/blks) --------- ----- ------------- ---- ---- ---- --- --------------- Spare disks for block or zoned checksum traditonal volumes or aggregates spare 9a.24 9a 1 8 FC:A 1 FCAL 10000 34000/69532000 34190/70022840 spare 9a.29 9a 1 13 FC:A 1 FCAL 10000 34000/69532000 34190/70022840 Pool0 spare disks (empty)

Step

Action

Enter the following command:

aggr status -s

Result

If there are hot spare disks, a display like the following appears, with a line for each spare disk, grouped by checksum type:

Pool1 spare disks

RAID Disk   Device  HA  SHELF BAY  CHAN   Pool  Type  RPM  Used (MB/blks)  

Phys(MB/blks)

---------   -----   -------------  ----   ----  ----  ---   ---------------

Spare disks for block or zoned checksum traditonal volumes or aggregates

spare        9a.24  9a   1      8  FC:A    1    FCAL  10000  34000/69532000

34190/70022840

spare        9a.29  9a   1     13  FC:A    1    FCAL  10000  34000/69532000

34190/70022840

Pool0 spare disks (empty)

Displaying the number of hot spare disks with FilerView

To ascertain how many hot spare disks you have on your storage system using FilerView, complete the following steps.

Step	Action
1	Open a browser and point to FilerView (for instructions on how to do this, see the chapter on accessing the storage system in the System Administration Guide).
2	Click the button to the left of FilerView to view a summary of system status, including the number of disks, and the number of spare and failed disks.