Administrator Guide

Table 43. Glossary of ME4 Series terms (continued)
Term Definition
to each other, and they both maintain a peer connection with the other. Asynchronous
replication of volumes may occur in either direction between peer systems configured in a
peer connection. See also peer connection.
PFU Partner firmware update. The automatic update of the partner controller when the user
updates firmware on one controller.
PGR Persistent group reservations.
PHY One of two hardware components that form a physical link between devices in a SAS network
that enables transmission of data.
point-to-point Fibre Channel Point-to-Point topology in which two ports are directly connected. pool See
linear pool, virtual pool.
POST Power-on self test. Tests that run immediately after a device is powered on.
primary system The storage system that contains a replication set’s primary volume. See also replication set,
secondary system.
primary volume The volume that is the source of data in a replication set and that can be mapped to hosts.
The primary volume exists in a primary (linear storage) or pool (virtual storage) in the primary
storage system.
PSU Power supply unit
quick rebuild A virtual-storage feature that reduces the time that user data is less than fully fault-tolerant
after a disk failure in a disk group. The quick-rebuild process rebuilds only data stripes that
contain user data. Data stripes that have not been allocated to user data are rebuilt in the
background.
RAID head See controller enclosure.
RBOD “RAID bunch of disks.” See controller enclosure.
read cache A special disk group, comprised of SSDs, that can be added to a virtual pool for the purpose of
speeding up read access to data stored on spinning disks elsewhere in the pool. Read cache is
also referred to as read flash cache.
read flash cache See read cache.
recovery In an active-active configuration, recovery is the act of returning ownership of controller
resources to a controller which was offline from its partner controller. The resources include
volumes, cache data, host ID information, and LUNs and WWNs. See also read cache.
remote syslog support See syslog.
replication Asynchronous replication of block-level data from a volume in a primary system to a volume in
a secondary system by creating an internal snapshot of the primary volume and copying the
snapshot data to the secondary system via Fibre Channel or iSCSI links.
replication set For virtual replication, a container that houses the infrastructure upon which replications are
performed. It defines a relationship between a primary and secondary volume for the purposes
of maintaining a remote copy of the primary volume on a peer system. See primary volume,
secondary volume.
replication snapshot history As part of handling a replication, the replication set will automatically take a snapshot of the
primary and/or secondary volume, thereby creating a history of data that has been replicated
over time. This feature can be enabled for a secondary volume or for a primary volume and its
secondary volume, but not for a volume group.
repurpose A method by which all data on a system or disk is erased in an FDE-capable system.
Repurposing unsecures the system and disks without needing the correct passphrase. See
also FDE, passphrase.
RFC Read flash cache. See read cache.
SAS Serial Attached SCSI.
Glossary of terms 187