HP MSA 2040 SAN Storage - Manual (Page 31)

Glossary 31
secondary volume The volume that is the destination for data in a replication set and that is not accessible to
hosts. For disaster recovery purposes, if the primary volume goes offline, a secondary
volume can be designated as the primary volume. The secondary volume exists in a
secondary vdisk in a secondary (or remote) storage system.
The contents of a secondary volume are in a constant state of flux and are not in a
consistent state while a replication is in process. Only snapshots that are associated with a
secondary volume are data consistent.
SES SCSI Enclosure Services.
single-port disk A disk that is connected to both controllers so its data path is not fault-tolerant. A single-port
disk’s type is shown as SAS-S or SATA-S.
snap pool A volume that stores data that is specific to snapshots of an associated master volume,
including copy-on-write data and data written explicitly to the snapshots. A snap pool
cannot be mapped.
snapshot A “virtual” volume that preserves the state of a master volume’s data as it existed when the
snapshot was created. Data associated with a snapshot is recorded in both the master
volume and in its associated snap pool. A snapshot can be mapped and written to. The
capability to create snapshots is a licensed feature. Snapshots that can be mapped to hosts
are counted against the snapshot-license limit, whereas transient and unmappable
snapshots are not.
SRA The HP MSA Storage Replication Adapter.
SRM VMware vCenter Site Recovery Manager.
ULP Unified LUN Presentation. A RAID controller feature that enables a host to access mapped
volumes through any controller host port. ULP incorporates Asymmetric Logical Unit Access
(ALUA) extensions.
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 and disk. Unwritable cache is also called orphan data.
vdisk A “virtual” disk comprising the capacity of one or more disks. The number of disks that a
vdisk can contain is determined by its RAID level.
volume A portion of the capacity of a vdisk that can be presented as a storage device to a host.
volume copy An independent copy (clone) of the data in a volume. The capability to create volume
copies makes use of snapshot functionality.
WWN World Wide Name. A globally unique 64-bit number that identifies a node process or
node port.
WWNN World Wide Node Name. A globally unique 64-bit number that identifies a node process.
WWPN World Wide Port Name. A globally unique 64-bit number that identifies a node port.