The Basics of Reliable Distributed Storage Networks

姓 名 : 冼炳基學 號 : 927479

Outline Introduction & Why use DSN ?? What is SAN(Storage Area Network) ?? What is NAS(Network-Attached Storage) ?? Distributed SAN Application Distributed NAS Application SAN or NAS ?? Future directions : IP storage Summary

Storage networks Introduction Increase storage efficiency and data availability Permit user quickly and efficiently perform

information management functionBackup and recoveryData mirroringDisaster recoveryData migration

Efficient of stored data greater than traditional “islands of storage”

Manage access data to increase performance , survivability and control costs

Why use DSN ?? (1) Geographical and distances

Ensure Data survivability over wide geographical areas Provide data synchronization over large distances

New regulatory requirementsSarbanes-Oxley ActHealth Insurance Portability and Accountability ActSecurities and Exchange Commission

Serial optical-fiber-based storage protocolsEscon (Enterprise System Connection)Fiber Channel

Why use DSN ?? (2) Bus-based protocols limited to a few meters Native-mode Escon and Fiber Channel

transmission more than 10 kilometers Repeaters or link extenders as far as 100

kilometers Storage data travel over MANs and WANs using

transport protocolsATM (Asynchronous Transfer Mode)Sonet (Synchronous Optical Network)WDM (Wavelength-Division Multiplexing)IP (Internet Protocol)

What is SAN (Storage Area Network)

One common storage network Computing and storage nodes via fabric of

network switches Switched fabric support multiple simultaneous

full-bandwidth connections A common backup server connect to any storage

device for scheduled or manual backup Employ a gateway provide MAN of WAN

interworking and protocol translation

SAN implementation

What is NAS (Network-Attached Storage)

Consists of a file manager attached to a LAN NAS difference with SAN

NAS serves file-structured data to clients

SAN serves block-structured data to application servers

Some NAS implementationNAS head to serves files to its clients

Attaches to a back-end SAN to manage block-structured data

Two issues for grographic range of NASDistance limitations inherent in LAN protocols

Use of a distributed SAN to provide backend storage for a NAS

NAS architectures

Distributed SAN Application

Storage integration Remote backup and restore Disk mirroring Data migration Business continuity and disaster recovery Remote operation of peripheral devices Mainframe and open-systems connectivity

Storage integration Using DSN to share disks and intergrate storage

across a wide grographic area Useful in amount of stored data is large

Database of genetic informationMultimedia or video serversMultiple servers update a common database

User don’t know where the data’s acutal physical location

Must limit data access to one user at any timeEmploy a locking mechanism

Shared-storage configuration

Remote backup and restore Non-real-time backup and restore from a remote

location Traditionally remote backup defect

Time-consumingDisruptive processDedicated personnel and equipment

Back up automatically across the MAN of WAN to tape or disk

Restore data from the backup copy across the MAN of WAN

Remote backup and restore

Disk mirroring Near-real-time mirror data to multiple disk Mirroring vs. backup

data availability cost

Synchronous vs. Asynchronous mirroring Local system log change immediately then

periodically logged change to remote system Forms of disk mirroring

Processor-centricStorage-centricSplit-mirror

Processor vs. storage -centric

Split-mirror Use a third mirror disk

Increase reliability

Minimize the possibility of data loss

Normal operation vs. copying data operation Optimum performance and minimal disruption The better solution for perform copy operation

Read-only can continue normally

Frozen image

Two basic ways to resynchronize third mirrorOverwrite all data to third disk from the other two

Use a transaction log to update changed blocks

Split-mirror architecture

Data migration Efficiently move large volumes of data Previously an awkward process

Need to copy volumes of data to type

Physically transprot to new location

Disrupting day-to-day processing

Storage networks provide an elegant solutionMirroring or backup can create a new copy at new location

New location copy can intend of old location copy at a specified time

Business continuity and disaster recovery

DSN are important for this require Loses data

Using standard backup and restore

mirroring

Loses processing capabilityProcessing continue by secondary site

Either site becomes inoperativeOther site can continue full processing

Remote operation of peripheral devices

Use storage protocols to remotely orperate peripheral devices

Printers

Check sorters

Perform remote-peripheral operationSAN

Mainframe storage architectures

Mainframe and open-systems connectivity

Application for connectivity Integration of e-commerce and mainframe-based applicationData warehousingBackup and recovery

Moving data among mainframe and open systemsLANFTP

Transfer the data directly between storage subsystems is faster

Gateway or bridge translates between Escon or FiconFicon storage protocol used in mainframe channel subsystem and SCSIFiber Channel used in open systems storage network

Mainframe and open-systems connectivity architecture

Distributed NAS Application

Distrubute NAS application in two way

Using switched gigabit EthernetEnable NAS file managers to be 5 kilometers

Production LAN without needing repeaters

For NAS head configurationDistribute the back-end SAN across multiple sites

Using any of distribute SAN applications

SAN or NAS ?? NAS

A short-term tactical solutionUse an existing Ethernet LANPerformance for smaller installations of less than 5 Tbytes)

SANFor large installations(greater than 5 TbytesWhere management and reliabilityMultisite data sharing and replicationLong-term strategic solution

SAN and NAS are beginning to convergeA NAS head with a SAN back end identical to SANNAS and SAN as two different views of the same data

Future directions : IP storage

Using internet and TCP/IP to transport block storage data

Ubiquity and availability of internet technologies

Cost and performance advantages of internet technologies

New application over internetiSCSI (Small Computer Systems Interface Protocol over the Internet)

FCIP (Fibre Channel over TCP/IP)

iFCP (Internet Fibre Channel Protocol)

Think of IP storage as a compatible technology

Summary Distrubuted storage applications improve the efficiency Remote backup and mirroring improve reliability Business continuity and disaster recovery enable

enterprises to recover quickly and transparently Storage protocols and gateway enable data transfer

between mainframe and open-systems NAS provide shared file access for clients using LAN Integrate with SAN to provide truly distributed metwork

capabilities