28 January 2011

Storage Area Networks PART 2 : Protocol and Devices

PROTOCOLS

FCIP: Entire Fibre Channel Frame Over IP

Fibre Channel Over TCP/IP (FCIP) describes mechanisms that allow the interconnection of islands of Fibre Channel storage area networks over IP-based networks to form a unified storage area network in a single Fibre Channel fabric. FCIP relies on IP-based network services to provide the connectivity between the storage area network islands over local area networks, metropolitan area networks, or wide area networks.

FCP: Fibre Channel Protocol

Fibre Channel Protocol (FCP) is the interface protocol of SCSI on the Fibre Channel.

iFCP: Internet Fibre Channel Protocol

Internet Fibre Channel Protocol (iFCP) is a gateway-to-gateway protocol, which provides fibre channel fabric services to fibre channel devices over a TCP/IP network. iFCP uses TCP to provide congestion control, error detection and recovery

iSCSI: Internet Small Computer System Interface

Internet Small Computer System Interface (iSCSI) is a TCP/IP-based protocol for establishing and managing connections between IP-based storage devices, hosts and clients, which is called Storage Area Network (SAN)

iSNS: Internet Storage Name Service

iSNS facilitates scalable configuration and management of iSCSI and Fibre Channel (FCP) storage devices in an IP network, by providing a set of services comparable to that available in Fibre Channel networks. iSNS thus allows a commodity IP network to function at a comparable level of intelligence to a Fibre Channel fabric.

NDMP: Network Data Management Protocol

The Network Data Management Protocol (NDMP) is an open protocol for enterprise-wide network based data management. NDMP defines a network-based mechanism and protocol for controlling backup, recovery, and other transfers of data between primary and secondary storage.

The NDMP (version 5) architecture is based on the client server model. The backup management software is considered the client, namely NDMP data management application (DMA)

SAS: Serial Attached SCSI

Serial Attached SCSI (SAS) is an evolutionary replacement for the Parallel SCSI physical storage interface. Serial Attached SCSI offers much faster communication and easier configuration. In addition, Serial Attached SCSI provides device compatibility to Serial ATA and uses similar cabling.

SCSI: Small Computer System Interface

Small Computer System Interface (SCSI), an ANSI standard, is a parallel interface standard used by Apple Macintosh computers, PCs, and many UNIX systems for attaching peripheral devices to computers. SCSI interfaces provide for faster data transmission rates than standard serial and parallel ports. In addition, you can attach many devices to a single SCSI port. There are many variations of SCSI: SCSI-1, SCSI-2, SCSI-3 and the recently approved standard Serial Attached SCSI (SAS).

Devices

Disk Array

A disk array is a disk storage system which contains multiple disk drives. It is differentiated from a disk enclosure, in that an array has cachememory and advanced functionality, like RAID and virtualization.

Components of a typical disk array include:

Disk array controllers
Cache memories
Disk enclosures
Power supplies

Typically a disk array provides increased availability, resiliency and maintainability by using additional, redundant components (controllers, power supplies, fans, etc.), often up to the point when all single points of failure (SPOFs) are eliminated from the design. Additionally those components are often hot-swappable.

Typically, disk arrays are divided into categories:

Network attached storage (NAS) arrays
storage area network (SAN) arrays:
Modular SAN arrays
Monolithic SAN arrays
Utility Storage Arrays
Storage virtualization

Tape Devices

A tape library, sometimes called a tape silo, tape robot or tape jukebox, is a storage device which contains one or more tape drives, a number of slots to hold tape cartridges, a barcode reader to identify tape cartridges and an automated method for loading tapes (a robot).

Optical JukeBox

An optical jukebox is a robotic data storage device that can automatically load and unload optical discs, such as Compact Disc, DVD, Ultra Density Optical or Blu-ray disc and can provide terabytes and petabytes of tertiary storage. The devices are often called optical disk libraries, robotic drives, or autochangers. Jukebox devices may have up to 2,000 slots for disks, and usually have a picking device that traverses the slots and drives. The arrangement of the slots and picking devices affects performance, depending on the space between a disk and the picking device. Seek times and transfer rates vary depending upon the optical technology.

Jukeboxes typically contain internal SCSI or SATA based recordable drives (CD-ROM, CD-R, DVD-ROM, DVD-R, DVD-RAM, UDO or Blu-ray) that connect directly to a file server and are managed by a third party jukebox management software. This software controls the movement of media within the jukebox, and the pre-mastering of data prior to the recording process

references:

http://en.wikipedia.org

http://www.javvin.com

http://www.skills2earn.com

20 January 2011

Storage Area Networks PART 1

Storage Area Network (SAN) is a high-speed subnetwork of shared storage devices. A storage device is a machine that contains nothing but a disk or disks for storing data. A typical SAN consists of a farm of disk arrays, CD-ROM, tape libraries, etc. interconnected with Fiber channel and connected to the outside world through a Fiber channel switch or bridge. The connections inside the boxes can be Fibre channel, SCSI, ATA or any other technology. Connecting all the storage devices into a network needs a plethora of hubs, bridges, routers, multiplexers, copper to optical converters, and other relevant devices as we do for a normal communications network

SANs originated to overcome the problems with network attached storage (NAS) devices, which - like ordinary servers - are difficult to manage and difficult to expand the capacity on. NAS devices also add to the traffic on the network and suffer from the delays introduced by the operating systems' network stacks. A SAN's architecture works in a way that makes all storage devices available to all servers on a LAN or WAN. As more storage devices are added to a SAN, they too will be accessible from any server in the larger network. In this case, the server merely acts as a pathway between the end user and the stored data.

A SAN is made up of a number of fabric switches connected in a network. The most common form of SAN uses the Fibre Channel fabric protocol (with Fibre Channel switches). Alternatively ISCSI could be used with IP switches. Connected to the SAN will be one or more Disk array controllers and one or more servers. The SAN allows the storage space on the hard disks in the Disk array controllers to be shared amongst the servers.

Few SAN Solution Providers

McDATA - providing SAN solutions.
Storage Area Network (SAN) Test Solutions
SAN software and hardware solutions
SAN Appliances provider
Storage Area Network Appliance from Stonefly
SAN Solutions by Rorke
SAN Solutions by Dot Hill
SAN Consulting Services
SAN solutions for data intensive, enterprise applications.
Tivoli Storage Area Networks (SAN) Solutions
SOFTEK - Storage Management Software - Storage Area Network (SAN) Solutions
Brocade develops Storage Area Network (SAN) infrastructure solutions that simplify the deployment and management of SANs
SAN Solutions from Sun
Simple, Safe, and Scalable SAN management solution
HCL Technologies - Storage Area Networks (SAN) - Solutions and Services
SAN Solutions by Legato
AT&T
HP Storage Works
DELL EMC

SAN Advantages

SAN Architecture facilitates scalability - Any number of storage devices can be added to store hundreds of terabytes
SAN reduces down time - We can upgrade our SAN, replace defective drives, backup our data without taking any servers offline. A well-configured SAN with mirroring and redundant servers can bring zero downtime.
Sharing SAN is possible - As SAN is not directly attached with any particular server or network, a SAN can be shared by all
SAN provides long distance connectivity - With Fibre channel capable of running upto 10 kilometers, we can keep our data in a remote, physically secure location. Fibre channel switching also makes it very easy to establish private connections with other SANs for mirroring, backup, or maintenance.
SAN is truly versatile - A SAN can be single entity, a master grouping of several SANs and can include SANs in remote locations.

SAN Disadvantages

SANs are very expensive as Fibre channel technology tends to be pricier and maintenance requires a higher degree of skill
Leveraging of existing technology investments tends to be much difficult. Though SAN facilitates to make use of already existing legacy storage, lack of SAN-building skills has greatly diminished deployment of homegrown SANs. So currently pre-packaged SANs based on Fibre channel technology are being used among the enterprises.
Management of SAN systems has proved to be a real tough one due to various reasons. Also for some, having a SAN storage facility seems to be wasteful one.
Also, there are a few SAN product vendors due to its very high price and very few mega enterprises need SAN set up.

Some Storage Technologies

Content Addressed Storage (CAS)

Fibre Channel

Teradata

Hierarchical Storage Management (HSM)

Internet Small Computer Systems Interface (iSCSI)

IP-based Storage

Network Attached Storage (NAS)

Optical Storage Technology

Storage Area Network (SAN)

Redundant Array of Inexpensive Disks (RAID)

Skills2Earn

28 January 2011

Storage Area Networks PART 2 : Protocol and Devices

List of SAN network management systems

20 January 2011

Storage Area Networks PART 1

Contributors