Administrator Guide
Storage Center Overview
Storage Center is a storage area network (SAN) that provides centralized, block-level storage that can be accessed by Fibre Channel,
iSCSI, or Serial Attached SCSI (SAS).
Storage Center Hardware Components
Storage Center consists of one or two controllers, switches, and might include one or more disk enclosures.
Controllers
A Storage Center controller provides the central processing capability for the Storage Center Operating System and managing RAID
storage. A
Storage Center is typically congured with a pair of controllers. In a dual-controller Storage Center conguration, the two
controllers must be the same model.
I/O cards in the controller provide communication with disk enclosures and servers that use the storage. Controllers provide two types of
I/O ports:
• Front-end ports – Hosts, servers, or Network Attached Storage (NAS) appliances access storage by connecting to controller Fibre
Channel I/O cards, FCoE I/O cards, or iSCSI I/O through one or more network switches. Some storage systems contain SAS ports that
are designated as front-end ports, which can be connected directly to a server. Ports for front-end connections are located on the back
of the controller, but are congured as front-end ports.
• Back-end ports – Enclosures, which hold the physical drives that provide back-end storage, connect directly to the controller. Fibre
Channel and SAS transports are supported through ports designated as back-end ports. Back-end ports are in their own private
network between the controllers and the drive enclosures.
Switches
Switches provide robust connectivity to servers, allowing for the use of multiple controllers and redundant transport paths. Cabling
between controller I/O cards, switches, and servers is referred to as front-end connectivity.
Enclosures
Enclosures house and control drives that provide storage. Enclosures are connected directly to controller I/O cards. These connections are
referred to as back-end connectivity.
Fibre Channel Switched Bunch of Disks (SBOD) and Serial Advanced Technology Attachment (SATA) enclosures are supported for existing
Storage Centers and for controller migrations only.
How Storage Virtualization Works
Storage Center virtualizes storage by grouping disks into pools of storage called Storage Types, which hold small chunks (pages) of data.
Block-level storage is allocated for use by dening volumes and mapping them to servers. The storage type and storage prole associated
with the volume determines how a volume uses storage.
Storage Center combines the following features to provide virtualized storage.
• Volumes – Allocate storage for use.
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