Embed Size (px)
Citation preview
Business Continuity
SRDFSymmetrix Remote Data Facility
Objectives
After completing this course, you will be able to:
• Explain the concept of Business Continuity
• List the benefits of Business Continuity regarding expenses incurred as a result of downtime
• Explain how EMC uses Local and Remote mirroring in its storage methodologies to maintain data protection
What is Business Continuity?
• Business Continuity is the preparation for, response to, and recovery from an application outage that adversely affects business operations
• Business Continuity Solutions addresses systems unavailability, degraded application performance, or unacceptable recovery strategies
Why Business Continuity?
Business Continuity – Obstacles of Availability
• Disaster (<1% of Occurrences)• Natural or man made
– Flood, fire, earthquake– Contaminated building
• Unplanned Occurrences (13% of Occurrences)
• Failure– Database corruption– Component failure– Human error
• Planned Occurrences (87% of Occurrences)
• Competing workloads – Backup, reporting– Data warehouse extracts– Application and data restore
Cost of Downtime Per Hour By Industry
Source: AMR Research
Investments
Retail
Insurance
$0 $100,000 $200,000 $300,000 $400,000
Telecom
Banking
Transportation
Manufacturing
Business Continuity Starts with Data Protection
• Local Mirroring is a method for protecting data by maintaining the data on two mirrored volumes within the same storage unit
• Remote Mirroring is a method for protecting data by maintaining the data on two mirrored volumes, with the volumes residing in different storage units
Without the Data there is no Recovery!
Data Protection with Disk Mirroring
Standard Disk
Mirrored Disk1991
Remote Mirror1994
Multiple Mirrors - Multiple Uses
Application BackupsApplication DevelopmentData Warehouse Extract
Recovery Testing
Application BackupsApplication DevelopmentData Warehouse Extract
Recovery Testing
High Availability Disaster Restart
High Availability Disaster Restart
Data Base Integrity Reporting
Quality AssuranceData Warehouse Load
Data Base Integrity Reporting
Quality AssuranceData Warehouse Load
BCVBCV
BCVBCV
Symmetrix BSymmetrix A
Symmetrix BSymmetrix A
1997Dynamic Disk
Mirrors
1997Dynamic Disk
Mirrors
1995Dual Remote
Mirrors
1995Dual Remote
Mirrors
2001Enterprise
Consistency Technology
2001Enterprise
Consistency Technology
BCVBCV
Backups and Decision Support at Multiple Sites withFull Protection of Volumes and Data Centers
EMC Business Continuity Solution Choices
Product Type Symmetrix CLARiiONLocal Replication TimeFinder/Mirror SnapView/Clone
TimeFinder/Clone CloneTimeFinder/Snap SnapView
Remote Replication SRDF MirrorViewSRDF/A MirrorView/A
SAN CopyReplication Automation SRDF/AR
SDMMERM ERM
Tape Replacement CopyCrossCluster GeoSpanI/O Path Failover PowerPath PowerPath
SRDF Foundations
After completing this course, you will be able to:
• Identify the functional concepts of SRDF
• List the benefits of SRDF
• Note the differences of the various EMC Symmetrix Remote Replication Solutions
The SRDF Product Family
• Offers solutions for many different disaster recovery and business continuance scenarios
• Consists of three base solutions– SRDF/Synchronous
– SRDF/Asynchronous
– SRDF/Data Mobility
• Consists of four add-on solutions– SRDF/Consistency Groups
– SRDF/Automated Replication
– SRDF/Cluster Enabler
– SRDF/Automated Availability Manager
Remote ReplicationRemote Replication
SRDF/SSynchronous for Zero Data Loss
SRDF/AAsynchronous for
Extended Distances
SRDF/DMEconomical Data
MobilitySR
DF
Fam
ilySR
DF
Fam
ily
Add-On Functions
SRDF/CGConsistency
Groups
SRDF/ARAutomated Replication
SRDF/CECluster Enabler
SRDF/AAMAutomated Availability
Manager
Remote ReplicationRemote Replication
SRDF/SSynchronous for Zero Data Loss
SRDF/AAsynchronous for
Extended Distances
SRDF/DMEconomical Data
Mobility
Remote ReplicationRemote Replication
SRDF/SSynchronous for Zero Data Loss
SRDF/AAsynchronous for
Extended Distances
SRDF/DMEconomical Data
MobilitySR
DF
Fam
ilySR
DF
Fam
ilySR
DF
Fam
ilySR
DF
Fam
ily
Add-On Functions
SRDF/CGConsistency
Groups
SRDF/ARAutomated Replication
SRDF/CECluster Enabler
SRDF/AAMAutomated Availability
Manager
Add-On Functions
SRDF/CGConsistency
Groups
SRDF/ARAutomated Replication
SRDF/CECluster Enabler
SRDF/AAMAutomated Availability
Manager
Symmetrix Remote Data FacilityData mirroring between physically separate Symmetrix systems
l Foundation for Symmetrix based disaster restart solutions
l Host operating systems, DBMS, file-system independent
l Bi-directional source-to-target(s) architecture
l Architecture uses delta technology (Track Tables)
– only changed data copied
ECC/OE Metro East
SRDF
SRDF
Production AMirror A
Production BMirror B
l Synchronous Model Semi-sync Model Adaptive Copy Mode
SRDF Source and Target Volumesl Symmetrix Logical Volume types:
– SRDF Source or R1 Volumes - Primary Volume with Read/Write (R/W) access to local host
– SRDF Target or R2 Volumes - Secondary Volume typically Write Disabled (WD) to secondary host
l The attached host is unaware of SRDF protection
• Locally Protected SRDF Source Volume:– Remote mirror “floats” and uses next available
mirror position– Allows for dynamic creation of SRDF volumes
WDRWSource
M1 M4M3
Target
M4M2 M3M1M2
l Locally Protected SRDF Target Volume:– Remote mirror “floats” and uses next available
mirror position– Allows for dynamic creation of SRDF volumes
SRDF Connectivity• SRDF over ESCON
– Direct Fiber, Multimode ~ 3 Km/cable segment– Fiber Repeaters/Converters (McData 9191) ~ 30 Km/cable segment, maximum of
three repeaters– Other Fiber Repeaters/Converters ~ 20 Km/cable segment, maximum of three
repeaters– DWDM, WDM (MAN) ~ 200 Km– LAN/WAN - T1/E1, T3/E3, ATM, IP ~ Unlimited
• SRDF over Fibre Channel– Direct Fiber, Multimode ~ 500 m/cable segment– Direct Fiber, Singlemode ~ 10 Km/cable segment– FC-Switch to FC-Switch ~ 60 Km, single-mode throughout entire SRDF path– DWDM (MAN) ~ 200 Km– LAN/WAN – IP ~ Unlimited
• SRDF over GigE– Native SRDF IP support– 850 nm multimode ports– 256 KB buffers for extended distance
Local campus Implementations• This solution enables units to be up to 66 km apart
– ESCON Direct Attach• Distance of up to 3 km • Throughput up to 14 MB/s
– Direct Fibre Channel Attach (Point-to-Point)• Distance of up to 10 km • Throughput up to 55 MB/s
– Switched Fibre Channel Attach • Distance of up to 10 km
– GigE• Enables direct Symmetrix-to-IP network attachment• Allows Symmetrix to access existing Ethernet infrastructure
Symmetrix
Connectrix
Fibre ChannelFibre Channel
Symmetrix
ISL
Connectrix
Fibre ChannelFibre Channel
Metropolitan Area Network Implementations
• The MAN solution enables units to be up to 100 km apart • Three Optical Link Configurations between 60 km and 100 km
– ESCON with Repeaters– ESCON via DWDM– Switched Fibre Channel via DWDM
Symmetrix Symmetrix
NortelOptera
Metro 5200
NortelOptera
Metro 5200
Connectrix Connectrix
DWDMDark Fiber
Fiber FiberFiberFiber
Extended Distance Implementations• Extended Distances range from 100 km up to trans-oceanic or trans-
continental length • Communication options include:
– T1/T3, E1/E3– Synchronous Optical Networks (SONET)– ATM-OC3– IP
100 Mb Ethernet
Router
SRDF w/ FarPoint
100 Mb Ethernet
IP Network
Symmetrix Symmetrix
SRDF w/ FarPoint
Router
Remote Link Director (RLD)
RemoteLink
Director
RemoteLink
Director
RemoteLink
Director
RemoteLink
DirectorSource Target
• Remote Link Directors (RLDs) use a modified ESCON protocol to manage data transfer to the remote Symmetrix
• Designated as either “RA1” or “RA2”– Configured in pairs to eliminate single points of failure
• Communications path is either fiber optics or T1/T3 depending on distance between sites
• Remote Link Directors may be assigned to an RA group• SRDF Volumes are assigned to a RLD or RLD group when configured
Remote Fibre Director (RFD)• Uses the Fibre Channel protocol to facilitate data
transfer between two Symmetrix systems• Fibre adapter cards designated only as “RAF”
rather than “RA1” or “RA2” within ESCON– Fibre Channel communication is peer-to-peer
rather than ESCON “master” and “slave”– Terms “Source Volume(s)” and “Target
Volume(s)” remain however• Ability to use one of the two RAF processors for
Fibre Channel host connection • Two types of RAF cards are available
– Both ports support multi-mode fiber optic transmission (500 m max. with 50 micron cable)
– One port supports multi-mode, one port supports single-mode fiber optic transmission
Source
RFD
RFD
Target
RFD
RFD
SRDF Configuration
Symmetrix A RA1
RA1Source
Symmetrix BRA2
RA2 Target
Symmetrix A RA1
RA1
Symmetrix BRA2
RA2Source TargetTarget Source
Symmetrix A Symmetrix BRA1
RA1
RA2
RA2Source TargetSource Target
RA2RA2
RA1RA1Target SourceTarget Source
Uni-Directional
Bi-Directional
Dual Configuration
SRDF Flexible Configuration OptionsSymmetrix A RFD
RFDSource Source
Symmetrix B RFD
RFDSource Source
Symmetrix CRFD
RFD TargetTarget
RFD
RFDTargetTarget
Multiple Source Symmetrix to a Single Target Symmetrix
Symmetrix A RFD
RFDSource Source
RFDRFDSource Source
Symmetrix BRFD
RFD Target
Symmetrix CRFD
RFD Target
Single Source Symmetrix to Multiple Target Symmetrix
Target
Target
Switched SRDF
RF
R1
R2
RFR1
R2
RF
R2RF
R1
Symmetrix 1Source to Symmetrix 2Source to Symmetrix 4
Symmetrix 2Target for Symmetrix 1
Symmetrix 3Target for Symmetrix 4
Symmetrix 4Source to Symmetrix 3Target for Symmetrix 1
l RF Directors no longer Source or Targetl Primary/Secondary R1/R2 relationship determines
mirroring direction
Connectrix(s)
Concurrent SRDF
• One R1 can be paired with two R2 devices, concurrently
Source
M1 M4M2 M3
M1 M4M2 M3
M1 M4M2 M3
Target “A”
Target “B”
Dynamic SRDF• Enables user to dynamically define
relationships between R1 and R2 volumes
• Provides flexibility for user to tailor SRDF configuration to their changing application requirements
RF
R1
R2
RFR1
R2
RF
R2
R1
RF
R211
3
1
3
1. Grey R1 established with R2 in Symmetrix B2. Grey R1 relationship with R2 in Symmetrix B broken3. Grey R1 established with R2 in Symmetrix C
22
Symmetrix A
Symmetrix B
Symmetrix C
SRDF - Modes of Operation
• Two Primary SRDF Operational Modes– Synchronous– Semi-synchronous
• Two Secondary SRDF Operational Modes– Adaptive Copy
• Write Pending• Disk Mode
– Domino Mode• Operational Modes are set on Symmetrix Logical
Volume level Using GUI or CLI and can be changed dynamically
• Performance, level of synchronization and IO serialization requirements determine appropriate mode
Performance Vs Availability
SRDF Modes of Operation
Source Target
SRDF links
I/O write received from host/server into cache of source
I/O is transmitted to the cache of the target
Receipt acknowledgment is provided by target back to cache of source
Ending status is presented to host/server
Synchronous Mode
SRDF Modes of OperationSemi-Synchronous Mode
Source Target
SRDF links
I/O write received from host/server into cache of source
Ending status is presented to host/server
I/O is transmitted to cache of target
Receipt acknowledgment provided by target back to cache of source
SRDF Modes of OperationAdaptive Copy Mode
Source Target
SRDF links
(and)I/O write received from host/server into cache of source
Ending status is presented to host/server
I/O is placed in SRDF queue
I/O is destaged to source (R1) volume, and an issue request is sent to Remote Link Adapter I/O is transmitted to cache of the target
Receipt acknowledgment is provided by target back to cache of source
SRDF Level of Synchronization
• Synchronous Mode– Source = Target
• Semi Synchronous Mode– Source ≅ Target– At most Source is 1 IO ahead of Target, per volume
• Adaptive Copy– Source ≠ Target– Source may be up to 65535 tracks per volume ahead
of Target– Skew value set per logical volume
