Related Topics; About Volumes; About Hosts - HP P2000 Reference Manual

Related topics

• Configuring dynamic spares
• Managing dedicated spares
• Managing global spares
• Using the Provisioning Wizard
• Creating a vdisk
• Viewing information about a vdisk

About volumes

A volume is a logical subdivision of a vdisk, and can be mapped to controller host ports for access by
hosts. A mapped volume provides the storage for a file system partition you create with your operating
system or third-party tools. The storage system presents only volumes, not vdisks, to hosts. A vdisk can have
a maximum of 128 volumes.
You can create a vdisk that has one volume or multiple volumes.
• Single-volume vdisks work well in environments that need one large, fault-tolerant storage space for
data on one host. A large database accessed by users on a single host that is used only for that
application is an example.
• Multiple-volume vdisks work well when you have very large disks and you want to make the most
efficient use of disk space for fault tolerance (parity and spares). For example, you could create one
10-TB RAID-5 vdisk and dedicate one spare to the vdisk. This minimizes the amount of disk space
allocated to parity and spares compared to the space required if you created five 2-TB RAID-5 vdisks.
However, I/O to multiple volumes in the same vdisk can slow system performance.
When you create volumes you can specify their sizes. If the total size of a vdisk's volumes equals the size of
the vdisk, you will not have any free space. Without free space, you cannot add or expand volumes. If you
need to add or expand a volume in a vdisk without free space, you can delete a volume to create free
space. Or, you can expand the vdisk and then either add a volume or expand a volume to use the new
free space.
You can use a volume's default name or change it to identify the volume's purpose. For example, a volume
used to store payroll information can be named Payroll.
You can create vdisks with volumes by using the Provisioning Wizard, or you can create volumes manually.
Related topics
• About vdisks
• About volume mapping
• About volume cache options
• Volume topics in
• Changing a volume's name or OpenVMS UID
• Changing a volume's cache settings
• Viewing information about a volume

About hosts

A host identifies an external port that the storage system is attached to. The external port may be a port in
an I/O adapter (such as an FC HBA) in a server, or a port in a network switch.
The controllers automatically discover hosts that have sent an
command to the storage system. Hosts typically do this when they boot up or rescan for devices. When the
command from the host occurs, the system saves the host ID. The ID for an FC or SAS host is its WWPN.
The ID for an iSCSI host is typically, but not limited to, its IQN. You can also manually create entries for
hosts.
You can assign a name to a host to make it easy to recognize for volume mapping. For a named host, you
can also select a profile that specifies whether the host allows use of LUN 0 for mappings. A maximum of
64 names can be assigned.
22 Getting started
on page 47
on page 53
on page 60
on page 57
on page 59
(page
on page 20
on page 23
on page 24
Provisioning the system
on page 55
on page 95
92) or all vdisks (page
on page 57
on page 54
inquiry
91)
command or a
report luns