Implementation: Dell | EMC SAN

Hardware Components

HBAs

Windows servers in a Dell | EMC SAN use Emulex HBAs. Depending on the actual environment your SAN is deployed in, different HBAs will be used.

Disk Processor Enclosure

	The disk processor enclosure (DPE) is the building block for the Dell | EMC family. It utilizes a pair of high-performance storage processors to deliver highly available RAID protection, high data throughput for sequential applications, and exceptionally high I/O performance for transaction processing.
The DPE houses up to ten dual-ported, Fibre Channel disk drives in a modular chassis and connects to host servers, hubs, and switches with a redundant pair of 100MB/s Fibre Channel loops. The three models available are:
Workgroup FC 5300 Midrange FC 4500 FC 4700
Components Storage Processors -- The SP provides the intelligence of the storage system. Using its own operating system (called base software), the SP processes the data written to or read from the disk modules, and monitors the modules themselves. An SP consists of a printed-circuit board with memory modules, and status lights. A second SP provides high availability for a storage system. The second SP provides a second route to a storage system and also lets the storage system use write caching for enhanced write performance. Storage Processor Cache -- Storage processors support both read cache and write cache to increase system performance. The allocation of cache for reads or writes for a system is configurable through software. Write cache must be protected to prevent data corruption. From the perspective of the operating system, data is written once it is in write cache. If a storage processor were to fail before data could be flushed from cache to disk, the result would be corrupted data. To prevent data corruption, the storage systems mirror write cache between the two storage processors and also provide battery backup for the write cache via standby power supplies. If one storage processor should fail, the remaining storage processor's write cache would be flushed and write caching would be disabled. Link Control Cards -- The LCC acts as a Fibre Channel hub for the disks in a disk enclosure and provides connectivity between the SP, disks, and other enclosures. The LCC module provides port bypass circuitry for failed drives and also monitors the environmental conditions. Hard Disks -- The storage systems use 100MB/s Fibre Channel drives. The drive format uses disk sectors at 520 bytes instead of the normal 512 bytes to provide eight bytes per sector for error detection handling. These additional bytes include linear checksums and status bits for the stripe. Disks 0 thru 2 (first three disks) have a reserved area (18MB) that is used to store base software and other configuration information. Disks 0 through 8 are known as the Cache Vault. This area is used to store cache information in the event of a power failure. The Persistent Storage Manager (PSM) is a 512MB private LUN that stores configuration information shared by both FC4700 storage processors. Standby Power Supplies -- The Standby Power Supply (SPS) is not a UPS. Rather, the SPS provides temporary power in the event of a power failure. If external power fails, the SPS provides sufficient AC power so that a storage processor can save the contents of the write cache to disk, then shut down the unit in an orderly manner. When power returns, the SPS recharges its cells automatically.

Disk Array Enclosure

	The disk array enclosure (DAE) is the capacity building block for the Dell | EMC family. The DAE provides a highly available packaging for up to ten dual-ported, high-performance, Fibre Channel disk drives in a modular chassis.
DAEs can be configured together and attached to a DPE to form highly available RAID subsystems. Connection to a DAE is through one or two Link Controller Cards (LCCs).

Switches

	Fibre Channel switches provide definable, high-bandwidth connectivity for complex, high-performance environments.
They support a centralized connectivity in storage networks and allow for non-disruptive device removal and insertion. The Fibre Channel switch provides connectivity for multiple Fibre Channel devices. Each port provides up to 200 MB/s of bandwidth. Available models include:
DS-8B DS-16B 8P-FC-2 DS-16B-2 (16P-FC-2) DS-32B-2

Tape Backup

	A PowerVault tape library becomes a central resource that can be shared between each server on the SAN. Because data throughput is significantly greater than the speed of network backup, windows for data throughput will be significantly shorter, allowing users more time to run production applications.
With SAN backup it is now possible to back up multiple devices at a time.