1 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 FUNDAMENTALS OF NETWORKING FOR BUSINESS CONTINUANCE Disaster Recovery Overview

222 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 In a Nutshell Elements of the Solution DR/BC Metrics Policies are adopted after Business Risk Assessment, determine tolerance for data loss and recovery time. Metrics to measure business impact RTO RPO RAO DR/BC Metrics Policies are adopted after Business Risk Assessment, determine tolerance for data loss and recovery time. Metrics to measure business impact RTO RPO RAO Data Center Inter-Connect Campus Metro Regional & National Data Center Inter-Connect Campus Metro Regional & National Data Protection Continuous Data Protection Array Based Data Replication Synchronous Asynchronous Data Protection Continuous Data Protection Array Based Data Replication Synchronous Asynchronous Site Selection Routing End Users to Applications Different Site Selection Mechanisms Site Selection Routing End Users to Applications Different Site Selection Mechanisms

333 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Enterprise RPO, RTO and RAO Policy Recovery Point Objective (RPO) What is the cost and impact of data loss? How much data loss is tolerable in event of disaster or failure? Recovery Time Objective (RTO) What is the maximum tolerable outage? When must operations resume after a disaster? Recovery Access Objective (RAO) How long to access recovered data and applications? RPO + RTO  measurable targets for BC/DR, and underlying Data Center, Application and Storage RAO  measurable target for underlying Network Infrastructure convergence and client access to Applications in the Data Center

444 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Recovery Time Objective and Recovery Point Objective How current or fresh is the data after recovery? How quickly can systems and data be recovered? time Disaster strikes time t 1 time t 2 Systems recovered and operational Recovery time Extended Cluster Manual Migration Tape Restore secsmins hoursdaysweeks $$$ Increasing cost Recovery point Synchronous Replication secsminshoursdays Asynchronous Replication Periodic Replication Tape backup time t 0 $$$ Increasing cost Critical data is recovered

555 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Recovery Access Objective (RAO) User to Applications time Disaster strikes time t 1 time t 2 Systems recovered and operational Recovery time time t 3 Accessing recovered & operational systems (t 2 )  Recovery Time Objective (t 3 – t 2 )  Recovery Access Objective Networks have converged to provide a path to the applications and data

666 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 DATA CENTER INTERCONNECT _05_2005_X2

777 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Data Center Interconnect Options Data Center Core Aggregation Access Core Access Servers Storage SONET/SDH Network DWDM Network Campus Core IBM Metro Ethernet DC Interconnect WAN GE IBM GDPS 1/2 Gb FC/FICON

888 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Data Center Transport Interconnect Technologies for IP Transport Dark Fiber CWDM DWDM SONET/SDH IP Data Center CampusMetro RegionalNational Increasing Distance Multi-Services 2Gbps 2Gbps lambda T1 or E1, T3 or E3, HSSI, ATM, PoS FCIP iSCSI GigE over Optical T1 or E1, T3 or E3, HSSI, ATM, PoS

999 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Data Center Transport Interconnect Technologies for SAN Extension Dark Fiber CWDM DWDM SONET/SDH FCIP Data Center CampusMetro RegionalNational Increasing Distance Sync Sync (2Gbps) Sync (2Gbps lambda) Sync Sync (Metro Eth) Async Async (1Gbps+) Async (< OC-12/STM4) Sonet/GigE Various WAN transports… …. Async (< DS3/E3) Optical Distance dependent on available BB_Credits BB_Credit Spoofing for extended distance

10 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 CWDM: Coarse WDM “Colored” CWDM SFPs (or GBICs) used in FC switches (no transponder) Optical multiplexing done in CWDM OADM (optical add/drop multiplexer) Passive (unpowered) device—Just mirrors and prisms Up to 30dB power budget (36dB typical) on SM fiber ~100km point-to-point or ~40km ring Provides for Client protection 1470nm 1490nm 1510nm 1530nm 1550nm 1570nm 1590nm 1610nm 1470nm 1490nm 1510nm 1530nm 1550nm 1570nm 1590nm 1610nm Mux/ Demux

11 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 DWDM: Dense WDM Higher density than CWDM 32 lambdas or more (protected) channels in narrow band around 1550nm at 100GHz spacing (0.8nm) EDFA amplifiable  longer distances Carrys 1, 2, 4 Gbps FC, FICON, GigE, 10GigE, ESCON, IBM GDPS Data Center to Data Center Protection options: Client, splitter, or linecard

12 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Coarse vs. Dense WDM Coarse (CWDM) Dense (DWDM) WavelengthsMax 8>8 (32 or more Protected) Spacing20 nm (1470nm–1610nm)0.8 nm Amplifiable Not w/ conventional EDFA (1550nm only) YES CostLOWHIGH Application Metro Access Campus and Data Center Large Enterprise/Service Provider Protection AvailableNoYes Type Characteristic

13 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Metro Ethernet Option What Does Ethernet as a LAN/MAN/WAN Transport Offer? Ethernet becomes the ubiquitous interface: single technology for LAN, MAN and WAN Efficient frame-based infrastructure: IP friendly Cost effective interface with flexible bandwidth offerings: 10/100/1000/10000 Mbps Geographical independence: Ethernet over Optical, IP or MPLS

14 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Ethernet Wire Service (EWS) Defines a point-to-point, port-based service No service multiplexing—“all-to-one” bundling Transparent to customer BPDUs Routers and switches can safely connect

15 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Ethernet Relay Service (ERS) Defines a VLAN-based point-to-point service (analogous to Frame Relay using VLAN tags as VC IDs) Service multiplexed UNI (e.g Q trunk) Opaque to customer PDUs (e.g. BPDUs) Router as CPE edge device

16 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 SITE SELECTION _05_2005_X2

17 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Site Selection Technologies Recovering the Front End Network Front End Network: DNS, RHI and BGP DNS (Application Aware) Used for load distribution, and proximity Route Health Injection (Application Aware) BGP (application unaware) Content Switch Active Standby Sites Load Distribution using IP Routing Content Router Active Active Sites Different Load Distribution algorithms

18 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Overview Site-Selection Storage Network Secondary Data Center FC SAN RAID FCIP Storage Network Primary Data Center FC SAN RAID FCIP Customer/ Partner Employee WAN Internet or Intranet Site Selection

19 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Active/Standby Internet ISPA Corporate WAN ISPB Primary for application 1 Primary for Application 2 Each application can have a unique IP address DC1DC2 Secondary for application 2 Secondary for application 1

20 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Advantages Typical Phase I deployment Could be implemented without the intelligent site selection front end (GSLB) Disadvantages Delay in failover manual switchover if without GSLB Under utilization of resources with no load sharing Active/Standby (cont)

21 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Active/Active Internet ISPA Corporate WAN ISPB Active for application 1 Active for application 1 Each application has 2 IP addresses DC1DC2 Active for application 2 Active for application 2

22 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Advantages Better use of resources due to load sharing Quick failover with no manual intervention Disadvantages Data mirroring in both directions Session persistence needs special care Active/Active (cont)

23 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Load Distribution Internet ISPA DC1DC2 Corporate WAN ISPB DNS server Content Router DNS server Content Router DNS resolution Load distribution

24 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Load Distribution Considerations Is the application stateful or stateless? Stateful applications need dns source-ip-hash methods or ACLs for static DNS mappings Stateless applications are easier to implement Are the clients coming from a mega-proxy (NAT’ed) environment? This might break the dns source-ip-hash methods Consider static DNS mappings with ACLs

25 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 DATA REPLICATION _05_2005_X2

26 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Data Replication Objectives Get the data to a recovery site – RPO Enable rapid restoration – RTO Facilitated by the SAN extension transport

27 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Replication and Mirroring Alternatives Disk replication Transparent to host Managed by disk subsystem e.g. EMC SRDF, HP CA EVA, HDS Truecopy, IBM PPRC, and others Continuous Data Protection (CDP) e.g. SANTap

28 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Array Based Replication: Concept Two arrays located on extended fibre channel fabric Read from local array Changes (Writes) replicated to remote array Replication managed by software in storage arrays Host server is unaware of replication Implementations are proprietary EMC: SRDF HDS: Truecopy HP: CA EVA IBM: PPRC And others … Multiple modes of operation Remote Storage Array Local Storage Array Host Server 1. Host Writes to local intelligent storage array 2. Storage array software replicates changes (writes) to remote array Normally Involves Two Round Trips per Write over Fibre Channel

29 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Replication: Modes of Operation Synchronous—All data written to cache of local and remote arrays before I/O is complete and acknowledged to host Asynchronous—Write acknowledged after write to local array cache; changes (writes) are replicated to remote array asynchronously

30 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 SAN Extension Network Synchronous Replication: I/O Detail Remote Storage Array Local Storage Array Host Server Write, LUN=5, LBA=12345, DL=8kB Transfer Ready FCP Data (2kB frames) SCSI Status=good I/O Service Time Write, LUN=5, LBA=12345, DL=8kB Transfer Ready FCP Data (2kB frames) SCSI Status=good tt t Round Trip Write I/O Is Complete at This Point—Local and Remote Arrays Identical

31 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 SAN Extension Network Asynchronous Replication: I/O Detail Remote Storage Array Host Server Write, LUN=5, LBA=12345, DL=8kB Transfer Ready FCP Data (2kB frames) SCSI Status=good I/O Service Time Write, LUN=5, LBA=12345, DL=8kB Transfer Ready FCP Data (2kB frames) SCSI Status=good Response from Local Array Returned Independently of Replication Process; IO Complete, But Arrays Not Identical tt t Round Trip Local Storage Array Replication Process and Protocol Is proprietary; Example Shows One Implementation

32 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 SAN Extension for Data Replication Extend the normal reach of a Fibre Channel fabric FC over SONET FC over IP (FCIP) Optical (DWDM, CWDM) FC SAN Extension Network Replication Shared Data Cluster Remote Host Access to Storage

33 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Fibre Channel Write Acceleration (FC-WA) Problem Performance of DR/BC applications inhibited by distance Solution Overcome limitations of SCSI writes FC write acceleration with SSM module on both ends Minimizes application latency Primary applications Synchronous replication Benefits Up to 25% increase in performance on synchronous application Extend Distances for DR/BC Applications Primary Data Center DR Data Center SSM FC WA

34 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Fibre Channel Write Acceleration FC WRITE XFER_RDY DATA STATUS FC WRITE XFER_RDY DATA STATUS FC XFER_RDY SSM Module Without FC Write AccelerationWith FC Write Acceleration Reduction in Latency of at Least One I/O Requirements for FC write acceleration SSM module Both initiator and target must be directly attached to the SSM module Benefits of FC write acceleration Improves response time for the storage applications Extended distance for BC/DR applications without performance impact

35 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 SAN Extension Design: High Availability Port channels increase resilience for high availability with FC or FCIP links Appears as a single logical link (Up to 16 member links) Protecting the fabric from network failure Route portchannel member links over diverse geographic paths Load balancing on SRCID/ DESTID or SRCID/DESTID/ OXID basis (Unidirectional per VSAN) SCSI exchange is smallest atomic unit, so frame order kept intact Site B Site A FC PortChannels

36 © 2005 Cisco Systems, Inc. All rights reserved. DC _05_2005_X2 Summary Determine the right RPO, RTO, and RAO for your business needs Recovering the front end mechanisms: BGP RHI DNS Recovering the back end: Data Replication & SAN Extension Transport options between Data Centers CWDM DWDM SONET/SDH Pure IP (e.g.: IP VPN) Metro Ethernet (Ethernet/GigE/10GigE)

37 © 2005 Cisco Systems, Inc. All rights reserved _05_2005_X2