Explain components of intelligent storage system?

➢ Intelligent Storage Systems are feature-rich RAID arrays that provide highly optimized 

I/O processing capabilities.

➢ These storage systems are configured with a large amount of memory (called cache) and 

multiple I/O paths and use sophisticated algorithms to meet the requirements of 

performance-sensitive applications.

➢ An intelligent storage system consists of four key components (Refer Fig 1.21):

Fig 1.21 Components of an Intelligent Storage System

1.14.1 Front End

➢ The front end provides the interface between the storage system and the host.

➢ It consists of two components:

i. Front-End Ports

ii. Front-End Controllers.

✓ Front End

✓ Cache

✓ Back end

✓ Physical disks

Front End

➢ The front end provides the interface between the storage system and the host.

➢ It consists of two components:

i. Front-End Ports

ii. Front-End Controllers.

➢ A front end has redundant controllers for high availability, and each controller contains 

multiple front-end ports that enable large numbers of hosts to connect to the intelligent 

storage system.

➢ Each front-end controller has processing logic that executes the appropriate transport 

protocol, such as Fibre Channel, iSCSI, FICON, or FCoE for storage connections.

➢ Front-end controllers route data to and from cache via the internal data bus.

➢ When the cache receives the write data, the controller sends an acknowledgment message 

back to the host.

Cache

➢ Cache is semiconductor memory where data is placed temporarily to reduce the time 

required to service I/O requests from the host.

➢ Cache improves storage system performance by isolating hosts from the mechanical 

delays associated with rotating disks or hard disk drives (HDD).

➢ Rotating disks are the slowest component of an intelligent storage system. Data access on 

rotating disks usually takes several millisecond because of seek time and rotational latency.

➢ Accessing data from cache is fast and typically takes less than a millisecond.

➢ On intelligent arrays, write data is first placed in cache and then written to disk.

Back End

➢ The back end provides an interface between cache and the physical disks.

➢ It consists of two components:

i. Back-end ports

ii. Back-end controllers.

➢ The back end controls data transfers between cache and the physical disks.

➢ From cache, data is sent to the back end and then routed to the destination disk.

➢ Physical disks are connected to ports on the back end.

➢ The back end controller communicates with the disks when performing reads and writes 

and also provides additional, but limited, temporary data storage.

➢ The algorithms implemented on back-end controllers provide error detection and 

correction, and also RAID functionality.

➢ For high data protection and high availability, storage systems are configured with dual 

controllers with multiple ports.

Physical Disk

➢ A physical disk stores data persistently.

➢ Physical disks are connected to the back-end storage controller and provide persistent data 

storage.

➢ Modern intelligent storage systems provide support to a variety of disk drives with 

different speeds and types, such as FC, SATA, SAS, and flash drives.

➢ They also support the use of a mix of flash, FC, or SATA within the same array.