Disk Arrays
RAID Recovery - Disk Arrays
Disk array is disk storage system consists of multiple disk drives and the integral part of the high performance storage system. It is designed to speed up the performance as well as increase protection against permanent data loss. It is different from disk enclosure where an array contains a cache memory with highly developed functionality like RAID as well as visualization.
Disk array controllers, cache memory, disk enclosure, and power supplies are common components for typical disk array. Generally, disk array offers high availability, flexibility, and maintainability with the help of extra, redundant components like power supplies and controller etc. up to the point of eliminating SPOFs (single points of failure) from the structure.
Disk arrays can be divided into five parts, they are: NAS, Modular SAN arrays, Monolithic SAN arrays, storage virtualization, and utility SAN arrays.
Network Attached Storage arrays:
NAS is a term which describes a complete storage system and is actually designed to be attached to a conventional network with its self LAN IP address. It offers file-level access though CIFS and NFS protocols. For example:
1. EMC Celerra family
2. NetApp Filer
3. HP Storage Works All-In-One Storage system
4. Sun Storage Tek 5000 family
Modular SAN array:
SAN is a network detached from LAN as well as WANs commonly used to connect multiple storage resources to a single or several servers. It offers block-level access to storage through SCSI based protocol including Fibre channel and iSCSI. Modular storage system, which contains independent modules, has scalability and also it can be raised in a standard rack cabinet. Module storage system is also known as departmental. For example:
1. HP Storageworks EVA family products
2. Fujitsu ETERNUS 4000/3000 series storage arrays
3. Hitachi WMS and AMS family products
4. Infortrend EonStor/EonRAID family
5. EMC CLARiiON
6. 3PAR InServ E-Class
7. Arena Maxtronic Janus Fibre Channel and iSCSI RAID system
8. IBM D4000/FESt T family of storage server
Monolithic arrays:
When basic configuration of an array is extremely large to fit into a standard rack cabinet, then the array is generally referred as Monolithic array. It is largely used where data is executed on large. Enterprises storage system offer protocols such as FICON and ESCON specially for mainframes in addition to iSCSI and Fibe Chennel for open systems SANs. For example:
1. EMC Symmetrix
2. IBM Enterprise Storage Server
3. Hitachi Lightning and TagmaStore USP family products.
4. IBM DS8000 series of storage server
5. Sun StorEdge 99xx (9970, 9985, 9990 OEM’s from Hitachi)
Storage virtualization:
It is hardware dependent software that functions as control program on the top of a standard OS platform
1. IBM SAN Volume Controller
2. EMC in Vista
3. RELDATA Unified Storage Gateway Application
4. Data Core Software Corporation SAN symphony and SANmelody Storage Server Virtualization
5. Falconstor IPStor Software
Utility Storage Array:
1. Pillar Data Systems Axiom
2. NetApp FAS GX series
3. 3PAR InServ Storage Server
