The Basics of Reliable Distributed Storage Networks

fullgorgedcutNetworking and Communications

Oct 24, 2013 (3 years and 11 months ago)

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The Basics of Reliable

Distributed Storage Networks




:
冼炳基




: 927479

Outline


Introduction & Why use DSN ??


What is SAN(
S
torage
A
rea
N
etwork) ??


What is NAS(
N
etwork
-
A
ttached
S
torage) ??


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 function

Backup and recovery

Data mirroring

Disaster recovery

Data 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 requirements

Sarbanes
-
Oxley Act

Health Insurance Portability and Accountability Act

Securities and Exchange Commission


Serial optical
-
fiber
-
based storage protocols

Escon (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 protocols

ATM (Asynchronous Transfer Mode)

Sonet (Synchronous Optical Network)

WDM (Wavelength
-
Division Multiplexing)

IP (Internet Protocol)

What is SAN (
S
torage
A
rea
N
etwork)


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 (
N
etwork
-
A
ttached
S
torage)


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 implementation

NAS head to serves files to its clients

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


Two issues for grographic range of NAS

Distance 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 information

Multimedia or video servers

Multiple 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 time

Employ 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
-
consuming

Disruptive process

Dedicated 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
-
centric

Storage
-
centric

Split
-
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 mirror

Overwrite 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 solution

Mirroring 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 capability

Processing continue by secondary site


Either site becomes inoperative

Other site can continue full processing

Remote operation of peripheral devices


Use storage protocols to remotely orperate
peripheral devices

Printers

Check sorters


Perform remote
-
peripheral operation

SAN

Mainframe storage architectures

Mainframe and open
-
systems connectivity


Application for connectivity

Integration of e
-
commerce and mainframe
-
based application

Data warehousing

Backup and recovery


Moving data among mainframe and open systems

LAN

FTP


Transfer the data directly between storage
subsystems is faster

Gateway or bridge translates between Escon or Ficon

Ficon storage protocol used in mainframe channel subsystem and SCSI

Fiber 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 Ethernet

Enable NAS file managers to be 5 kilometers

Production LAN without needing repeaters


For NAS head configuration

Distribute the back
-
end SAN across multiple sites

Using any of distribute SAN applications


SAN or NAS ??


NAS

A short
-
term tactical solution

Use an existing Ethernet LAN

Performance for smaller installations of less than 5 Tbytes)


SAN

For large installations(greater than 5 Tbytes

Where management and reliability

Multisite data sharing and replication

Long
-
term strategic solution


SAN and NAS are beginning to converge

A NAS head with a SAN back end identical to SAN

NAS 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 internet

iSCSI (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