SAN VS NASGROUP NO-13

INTRODUCTIONData is unquestionably the lifeline in todays digital organization. Storage solutions remain a top priority in IT budgets precisely because the integrety, availability and protection of data are vital to business productivity and success.

EVOLUTION IN STORAGE ARCHITECTURE

TYPES OF STORAGE TODAYDirect Attached Storage (DAS)Storage Area Networks (SAN)Network Attached Storage (NAS)

DAS - Direct Attached Storage DAS is the most basic storage subsystem that provides block-level storage, and it's the building block for SAN and NAS. A DAS system is directly attached to a server or a workstation, without a storage network in between.

DAS ARCHITECTURE

ADVANTAGESLower costOverall simplicity

DISADVANTAGESDas device is isolated from all others.Data accessibility becomes difficult in large business.

SAN(Storage Area Network)

DEFINITIONThe Storage Network Industry Association (SNIA) defines the SAN as a network whose primary purpose is the transfer of data between computer systems and storage elements.

WHAT IS A SAN?A SAN consists of a dedicated network that interconnects servers and their applications to storage resources with the use a switch or hub. (Hubs seldom seen any more.)

Storage resources usually consists of disks and tapes.

An adapter card on the server is connected by fiber optic or copper cabling to a SAN switch.

Disk arrays and tape devices are also connected to the switch, which brings all servers and storage devices into a peer-to-peer network.

SAN ARCHITECTURE

SAN CHARACTERISTICS

SANs are networked infrastructures designed to provide a flexible, high-performance, and highly scalable storage environment.

SANs accomplish this by enabling many direct connections between servers and storage devices such as disk storage systems and tape libraries.

High-performance Fiber Channel switches and Fiber Channel network protocols ensure that device connections are both reliable and efficient.

SAN TOPOLOGY

THE WIRES & PROTOCOLS BEING USED:

SAN solutions use Fiber Channel connections

SAN solutions utilizes Fiber Channel encapsulated SCSI setups

The dedicated network is usually fibre channel or iSCSI(Internet small computer system interface).

SAN INFRASTRUCTURE

SAN TERMINOLOGY

What type of network access does SAN employ?

Fibre channeliSCSIInfinibandCIM (Common Information Model)Bluefin (based on CIM)

GENERAL INFORMATION SANA SAN is primarily used in a large data environment for data storage. It is not possible to access a SAN without an intermediary unit (A server/Mainframe)They are expensive to setup, but easy to maintain. SANs also provide a central storage area for tape backups to be taken from.SAN Hard drives can be SCSI, ATA, or most commonly, fiber connection.ISU currently has two SANs in use. One runs the primary server cluster, and the other is used in the Library, as part of the DRP plan(in the works).

ADVANTAGESHigh availability Data transfer reliability Reduced traffic on the primary networkConfiguration flexibility High performanceHigh scalabilityCentralized managementMultiple vendor offerings

DISADVANTAGESMore expensive

APPLICATIONS

Mission-critical transaction-based database application processingCentralized data backupDisaster recovery operationsStorage consolidation

NAS(Network Attached Storage)

DEFINITIONThe Storage Network Industry Association (SNIA) defines the NAS as a class of systems that provide file services to host computers using file access protocols

WHAT IS NASNAS is shared storage on a network infrastructureNAS is network-centric. NAS provides security and performs all file and storage services through standard network protocols, using TCP/IP for data transfer, Ethernet and Gigabit Ethernet for media access, and CIFS, http, and NFS for remote file service

NAS ARCHITECTURE

NAS CHARACTERISTICS

NAS solutions are typically configured as file-serving appliances accessed by workstationsand servers through a network protocol. Most NAS connections reside between workstation clients and the NAS file-sharing facility. NAS enables organizations to quickly and easily add file storage capacity to their technologyinfrastructure.

NAS TOPOLOGY

THE WIRES & PROTOCOLS BEING USED:

NAS solutions utilize TCP/IP based networks, such as Ethernet, FDDI, or ATM .ATM NAS solutions use TCP/IP and NFS/CIFS/HTTP based networks

NAS INFRASTRUCTURE

NAS TERMINOLOGY

The NAS head represents the part of the NAS solution required for the clients to connect to the IO subsystem. Behind the NAS head, hundreds or thousands of GB of available IO storage may exist, but the clients have to access the IO space via the NAS head. A NAS head is also called a NAS Gateway (a system), which serves as the actual control function of a NAS

NFS (Network File System) is one of the communications protocols usually supported by NAS heads (for the communication with the network clients); particular in UNIX or Linux based solutions. It has to be pointed out though that NFS clients are available for just about any operating systems these days

The CIFS (Common Internet File System) protocol is primarily responsible for file sharing and communication with Windows (and Linux-based Samba) servers, and represents another commonly supported protocol for most NAS heads. Most Windows clients utilize CIFS to communicate with the NAS head. Both, NFS and CIFS utilize TCP/IP as the underlying communication facility.

GENERAL INFORMATION NASNAS devices are inexpensive and easy to setup. Can cause difficulty to maintain.

Each devices maintains its own IP address.

There is also no worries about server crashes.

Windows, MAC, and Unix all support access to a NAS device one way or another.

ADVANTAGES Few distance limitations

Simplified addition of file sharing capacity

Easy deployment and maintenance

DISADVANTAGESNAS systems are not 100% compatible with Microsoft Access Control Lists (ACL). With the exception of SQL, most database systems, such as Oracle or Microsoft Exchange, cannot work with filers, i.e. file servers, such as NAS appliances constitute. Data backup and replication are only ever possible on a file basis with NAS devices

APPLICATIONS

Small-block data transfer over long distancesLimited read-only database accessFile sharing and online storage.BackupsDuplication of images for frequently used software configurations for distribution. Increase online storage at particular locations for remote offices.

SAN VS NAS

SAN AND NAS DISTINCTIONS

SAN and NAS DistinctionsSANNASAlmost any machine that connects to a LAN (or isinterconnected to a LAN via a WAN) may utilize NFS,CIFS or HTTP protocol to connect to a NASServer class devices that are equipped with SCSI Fibre Channeladapters connect to a SAN. A Fibre Channel based solution has adistance limit of approximately 6 miles

A NAS identifies the data by file name and byte offset,transfers file data or metadata, and handles security, userauthentication, file lockingA SAN addresses the data by logical block numbers, and transfersthe data in (raw) disk blocks.

SAN and NAS DistinctionsSANNASA NAS allows greater sharing of information, especiallyamong different operating systemsFile Sharing is operating system dependent, and may not exist forall operating systems that are being used

File system is managed by the NAS head unitThe SAN servers manage the file system

Backups and mirrors are generated on files, not blocks(this may save bandwidth and time)Backups and mirrors require a block by block copy operation. Amirrored system has to be either identical, or greater in capacity(compared to the source)

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