TCP/IP WAN

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26 Οκτ 2013 (πριν από 3 χρόνια και 9 μήνες)

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Track 1: Data Protection over
Long
-
haul WANs

Dragon Slayer Consulting

Marc Staimer, President & CDS

marcstaimer@earthlink.net


26 April 2004

Agenda


Why over long
-
haul


Data Protection Apps


Data Characteristics


Trends


TCP Characteristics



Disconnect


TCP Conclusion


Solving TCP
Performance Problems


DP TCP Enhancers


Conclusion & Summary

Dragon Slayer Background


7 yrs sales


7 yrs sales mgt


10 yrs marketing & bus
dev


Storage & SANs


6 years consulting



Launched or participated


20 products


Paid Consulting


> 70 vendors


Unpaid Consulting


> 200 end users



Known Industry Expert


Speak ~ 5 events/yr


Write ~ 3 trade articles/yr


Why Data Protection

Over Long
-
Haul WANs?


Regulatory Compliance


HIPAA, Sarbanes
-
Oxley, GLBA or the Patriot Act


HIPAA fines = ~ $25k per violation


Sarbanes
-
Oxley fines = ~ $1M or 10 yr prison term


Protection against regional disasters


Hurricanes, tornados, earthquakes, floods, volcanoes


Terrorist attacks

Data Protection Applications


Volume Replication


Snapshot


Mirroring


Backup


Disk
-
2
-
Disk
-
2
-
Tape


ILM

Volume Replication (a.k.a. cloning)


Complete


Incremental changes


Large amounts of data

TCP/IP WAN

TCP/IP WAN

Snapshot


Complete


Incremental


Directories


Time based

Mirroring


Synchronous


Latency sensitive


Distance limited ~ 200KM


Asynchronous


Unlimited distance


Typically time stamped

TCP/IP WAN

Traditional Backup


Client
-
BU Server
-
Tape


Server
-
BU Server
-
Tape


Many
-
to
-
one

TCP/IP WAN

Disk
-
to
-
Disk
-
2
-
Tape


Server
-
External Disk
-
Tape


Server
-
Virtual Tape
-
Tape


TCP/IP WAN

ILM

a.k.a. Information Lifecycle Management


Policy or Wizard


Migrates data to lower cost storage


Based on policies, regulations, & data value

TCP/IP WAN

FC Array

SATA Array

Read
-
write

Tape

WORM

Data Protection Long Haul Trends


TCP/IP Networks


Shared


Perceived to be free


SONET


Dedicated


High performance Low Overhead

Audience Response

What WAN do you use for data protection

1.
TCP/IP

2.
SONET

3.
Both

4.
Neither

Market Trends


In a poll of over 200 End users


From SMB, SME, and Enterprise


56% = DP over TCP WANs


3% = DP over other ATM/SONET


29% = No DP over WAN


12% = Both TCP & ATM/SONET

Why TCP/IP WANs are so
Prevalent with Data Protection


Perception that they are free


Or at least very inexpensive


Piggyback on IP WAN networks


Evenings and Weekends

Characteristics of Data Protection


Big blocks of data


Can overwhelm standard IP routers


Not limited to nights & weekends


Time is very relevant


Time windows are getting smaller



Data Protection > OpEx Line Items

1.
Personnel

2.
Bandwidth

Headaches with TCP/IP WANs &
Data Protection


Designed for some packet loss


Typical = ~ 1%


Packet loss = retransmissions


Packet loss caused by


Congestion


Bit Error Rates


Jitter


Latency


Router buffer overruns

TCP 1985: Designed for LANs

1.
TCP Slow Start


Packet rate doubled


Per successful round trip

2.
Loss Events


Sending rate cut 50% per

3.
TCP Congestion Control


Sending rate increase by 1


Per successful round trip

1

Slow

Start

Congestion Control

x

x

x

x

x

x

x

2

3

x

x

x

x

X = packet loss

TCP 2004: LAN Protocol over the WAN

Same internal logic


Since 1985!

1.
Loss events on High BW


Induce large packet losses

2.
High Latency


Slower recovery


During congestion control

3.
Infrequent feedback


On changing route conditions


Based on packet loss events

3

1

Slow

Start

Congestion Control

x

x

x

2

DS3, 45Mb/s, high latency & loss

X = packet loss

TCP/IP WAN

TCP Resource Contention on Shared Links

Reduces Data Protection throughput

1.
Sporadic packet loss.

2.
Short & long distance
sessions


Contend for same
resources

3.
Router queues change
dynamically


From traffic bursts.

3

1

Slow

Start

Congestion Control

2

x

x

x

x

x

x

x

x

x

x

x

TCP: What really happens to long
distance sessions

1.
Packet loss events


Frequent for shared nets

2.
Loss events


Router buffer overruns


Affect other sessions


Lots of lost packets

3.
LD sessions beat down


By SD sessions

4.
Results


Low throughput


Random delays

3

1

Slow

Start

Long Distance

x

x

x

x

x

x

x

WAN Bandwidth (DS3) 45Mb/s

Short Distance

TCP/IP WAN

2


The Data Protection TCP WAN
Disconnect


As distance >, performance <


Worse with higher bandwidth


Data Protection Conclusion


Perception & reality do not match

Solving TCP Performance Issues While
Maintaining its Perceived Value


TCP enhancers


Proxies


Compressors


Caching/spoofing


Accelerators

Different Clever Technologies


TCP/IP Performance enhancing proxy


Eliminates TCP packet loss & latency issues


Compression


Increases payloads per packet


Compression increases from 2X to 400X


Caching (a.k.a. spoofing)


Acknowledges packets locally


Accelerators


Resequencing, QoS, concatenation, duplication elimination


Chatty protocol elimination


Shield

TCP/IP Network Shielding

Data protection packets

in a TCP/IP network

Bit Error

Rates

Network

Jitter

TCP/IP

Latency

Network

Congestion


Much > BW utilization!


Before compression


Shields TCP/IP Network


Bit Error Rates


Congestion


Jitter


Latency


Buffer Overflows

Router

buffer

Overflows


>

DS3 TCP/IP Performance
Enhancements


NetEx
-

HyperIP®


Orbital Data
-

IP Express

<

DS3 TCP/IP Performance
Enhancements


Expand
-

IP Accelerators


1800/4800/6800/9000 series


Peribit


SR20/50/55/80


Net Celera


T Series


River Bed
-

Steel Head


500/1K/2K/3K/5K


Orbital Data


IP Express LC

Caching Appliances


River Bed
-

Steel Head 500/1K/2K/3K/5K


CIFS & MAPI


Tacit
-

I
shared

Server


CIFS & NFS


Kashya
-

KBX4000


Includes volume replication, snapshot, & mirroring


File & block replication

TCP/IP WAN

Appliance

Appliance

Bi
-
directional

Data Protection Data Caveats


Needs TCP enhancement


Large amounts of data


Data migration


Volume replication


Snapshots


High IOPS


Bulk data transfers


Long distance


Big bandwidth


May not need it


Incremental data


Only changed data


Short time for net new data


Asynchronous mirroring


Short distance


Small bandwidth

Summary and Conclusions


Data protection apps over TCP WANs


Has significant throughput issues over distance


There are solutions


Different solutions work better for different apps


Compression is only a partial solution


Check your options


Find the one that works best with YOUR applications

Questions