Hardware manual

9–1
9 Basic volume operations
Basic volume operations consist of creating volumes, setting up access controls, and modifying volume attributes.
You can also clone a volume to create an exact copy.
About volumes
A computer uses an industry-standard iSCSI initiator to access a volume in a group. Most operating systems
provide an iSCSI initiator (in the form of an iSCSI driver or a host bus adapter), with a range of price and
performance options.
To access storage in a PS Series group, you allocate portions of a storage pool to volumes. Ea
ch volume appears on
the network as an iSCSI target. Computers with iSCSI initiators can connect to the target, which appears as a
regular disk.
When you connect to a volume, it appears
like a regular disk drive that you can format by using the normal
operating system utilities. As the group configuration changes, volumes continue to be accessible through the same
iSCSI targets, and no modifications are necessary.
You assign each volume a size (reported size) and a storag
e pool. The group automatically load balances volume
data across pool members. Optionally, you can reserve snapshot space or replication space for a volume.
For each volume (and snapshot), the group generates an iSCSI targ
et name, which you cannot modify. An iSCSI
target name includes a prefix (
iqn.2001-05.com.equallogic), a string, and the volume name. Initiators use
the target name to connect to a volume.
The following is an example of an iSCSI targ
et name for a volume with the name db3:
iqn.2001-05.com.equallogic:7-8b0900-6d0000000-001ebbc5d80sf0k0-db3
Access control records and other mechanisms protect your volume
s from unauthorized and uncoordinated access
by iSCSI initiators. See iSCSI target security on pa
ge 8-1.
You can use snapshots to protect volume data from mistakes, viruses,
or database corruption. To protect against
disasters, you can replicate volume data from one group to another.
About volume types
A PS Series group supports the following volume types:
• Standard volume. The default volume type is a standard volume. There are no restric
tions on a standard
volume. You can enable (and disable) thin provisioning on a standard volume.
• Template volume. A template volume is a type of volume that
is useful if your environment requires multiple
volumes that share a large amount of common data. When you write the common data to a standard volume,
you can convert it to a template volume and then create thin clones. Template volumes are read-only to protect
the common data.
• Thin clone volume. Thin clones are based on a template volume a
nd enable you to use space efficiently in
storage environments that require multiple volumes with a large amount of common data. After you create a
thin clone, you can write to the thin clone. See About template volumes and thin clones on
page 10-6.