Understanding freespace, Understanding freespace 6-17 – HP NetRAID-4M Controller User Manual

Page 123

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6-17

Working with Container Attributes

Understanding Freespace

Freespace is the space on an initialized disk that is not being used by
other RAID components. Containers are created from freespace.
When a container is deleted, its space is returned to freespace.

You specify freespace in terms of a SCSI device ID and, optionally, a
size as in the following example. If the

size

parameter is not

specified, the freespace defaults to the size of the first freespace area
available on the specified SCSI device. Note that offsets are not
specified for freespace. The offset used is the first offset that starts a
freespace area large enough to fit the number of bytes specified in
the

size

parameter. In the example, the freespace is indicated by a

combination of SCSI device ID and size. The SCSI device ID is
(1,2,0)

, and the size is 1G. See Understanding Channel Attributes in

Chapter 3 for a description of SCSI device IDs.

((1,2,0),1G)

Note:

When specifying freespace during a container create

volume operation, you must explicitly specify the SCSI
device’s channel, device ID, and logical unit number. You
cannot use any default values for the SCSI device. In
addition, you must also specify the size of the freespace(s).

To display a disk’s freespace, use the

disk show space

command,

as in the following example. In the example, the Usage column
indicates Free for each SCSI device, which means that each SCSI
device contains only freespace. The Size column indicates that each
SCSI device has 8.47GB of freespace.

HPN0> disk show space

Executing: disk show space

Scsi C:ID:L Usage Size

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

2:01:0 Free 64.0KB:8.47GB

2:02:0 Free 64.0KB:8.47GB

2:03:0 Free 64.0KB:8.47GB

2:04:0 Free 64.0KB:8.47GB

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