Administrator Guide

Table 43. Glossary of ME4 Series terms (continued)
Term Definition
• Performance, which uses SSDs (high speed)
• Standard, which uses enterprise-class spinning SAS disks (10k/15k RPM, higher capacity)
• Archive, which uses midline spinning SAS disks (<10k RPM, high capacity).
tier migration The automatic movement of blocks of data, associated with a single virtual volume, between tiers
based on the access patterns that are detected for the data on that volume.
tray See enclosure.
ULP Unified LUN Presentation. A RAID controller feature that enables a host system to access mapped
volumes through any controller host port. ULP incorporates ALUA extensions.
undercommitted The amount of storage capacity that is allocated to volumes is less than the physical capacity of the
storage system.
unmount To remove access to a volume from a host OS.
unwritable cache data Cache data that has not been written to disk and is associated with a volume that no longer exists or
whose disks are not online. If the data is needed, the volume’s disks must be brought online. If the
data is not needed it can be cleared, in which case it will be lost and data will differ between the host
system and disk. Unwritable cache data is also called orphan data.
UPS Uninterruptible power supply.
UTC Coordinated Universal Time.
UTF-8 UCS transformation format - 8-bit. A variable-width encoding that can represent every character in
the Unicode character set used for the PowerVault Manager and CLI.
vdisk See linear disk group.
virtual The storage-class designation for logical components such as volumes that use paged-storage
technology to virtualize data storage. See paged storage.
virtual disk group A group of disks that is configured to use a specific RAID level. The number of disks that a virtual disk
group can contain is determined by its RAID level. A virtual disk group can be added to a new or
existing virtual pool. See also virtual pool.
virtual pool A container for volumes that is composed of one or more virtual disk groups.
volume A logical representation of a fixed-size, contiguous span of storage that is presented to host systems
for the purpose of storing data.
volume copy An independent copy of the data in a linear volume. The capability to copy volumes makes use of
snapshot functionality.
volume group A user-defined group of volumes for ease of management, such as for mapping operations.
VPD Vital Product Data. Data held on an EEPROM in an enclosure or FRU that is used by GEM to identify
and control the component.
WBEM Web-Based Enterprise Management.
WBI Web-browser interface, called PowerVault Manager. The primary interface for managing the storage
system. A user can enable the use of HTTP, HTTPS for increased security, or both.
WWN World Wide Name. A globally unique 64-bit number that identifies a device used in storage
technology.
WWNN World Wide Node Name. A globally unique 64-bit number that identifies a device.
WWPN World Wide Port Name. A globally unique 64-bit number that identifies a port.
Glossary of terms 179