Dell Compellent Series 30 - Manual (Page 444)

436 Storage Center 5.5 System Manager User Guide
Storage Clustering
Storage Center software providing automatic controller failover through multiple controllers in an active-
active configuration. Fully mirrored, battery backup cache provides automatic restart in the event of a
controller failure.
Storage Interface (back end)
Refers to the storage interface of the Storage Controller.
Storage Pool
An undifferentiated pool of available disk space from which Storage Center draws creates volumes.
Storage Profile
A collection of rules that identify RAID level and drive types (tiers) on which data is stored. All volumes are
attached to a Storage Profile. Storage Profiles can be applied by default, per volume, to a group or all
volumes. If RAID levels or tiers in a Storage Profile change, data in volumes attached to that Storage Profile
is moved via Data Progression to the new RAID levels or tiers.
Storage Type
Pool of storage from which volumes are created. Storage Center is most efficient when all disks are
combined into one pool of storage. Data Progression can then store data with maximum efficiency. In some
circumstances, you can create additional based on redundancy and data page size.
Synchronous Replication
In synchronous replication, each write to the primary disk and the secondary (remote) disk must be
complete before the next write can begin. The advantage of this approach is that the two sets of data are
always synchronized. The disadvantage is that if the distance between the two storage disks is substantial,
the replication process can take a long time and slows down the application writing the data. See also
asynchronous replication.
T
Target System
The Storage Center system that receives replication data from an initiating Storage Center. See Initiator .
TCP/IP
Terminal Control Protocol/Internet Protocol
Tiers
Blocks of data that are stored according to its intended use. For example, data that has been accessed
within the last four progression cycles is stored on the highest tier, composed of the fastest disks. Data that
has not been accessed for the last 12 progression cycles is gradually migrated down to the lowest tier,
composed of slower, cheaper, larger disks.
Thin Provisioning
Volume sizes can be defined that are greater than the actual physical storage. Storage space is only used
when data is written. Thin Provisioning allows organizations to reduce their overall disk expenditures,
increase availability and achieve greater performance.