7 Must-Know Disaster Recovery Strategies

Jamie Gruener

Senior Analyst, Enterprise Infrastructure

The Yankee Group

What You Will Learn In This Session . .

1. The Main Goal: Bullet-proofing Disaster Recovery Strategies

2. Remote Replication vs. Mirroring Strategies 3. Disaster Recovery and Virtualization: A New Angle4. Integrating Mirroring and Replication into Disaster

Recovery Strategies5. Metro SANs: Options for Remote Mirroring And

Replication6. Your Network Options: Questions to Guide You7. The Outsourcing Alternatives: Things to Consider

The Goal: Bullet-Proofing Disaster Recovery Strategies

• You’ve heard the statistics– ~ $5 billion in computing infrastructure lost in 9-11 tragedy– Close to 100 businesses declaring disasters in NYC

• You’re here for a reason– 9-11 was a call to action for all of us– Disaster Recovery and Business Continuity Strategies must be

done – this is only one leg of a multi-leg strategy

• You’re entering a new era– It is now about Business Continuance and Risk Management– Preserving data is an imperative

Defining Terms: Remote Mirroring and Data

Replication• Remote Mirroring generates a mirrored image of data on two or more disks

• Data Replication scans data periodically for changes and copies new data to the other disk or file system on another system

• Factors to consider– Value of data (and lost data) being backed up– Costs for network bandwidth and software– Your existing infrastructure– Product features (OS, File System, Disk or Application)

Checklist

Measuring Data Protection: Point-in-Time to Synchronous

Data Protection

Network Bandwidth Consumed

Point In Time

Asynchronous

Synchronous

Tip

There will be a need formultiple tools to protect data

Lost Transactions Line of Tolerance

More

Less More

Semi-Synchronous

Questions to Consider When Looking At Remote Mirroring

and Replication– What are you protecting? (applications,

transactions, files, disks)– What level of protection do you need?

(We’ll come back to this!)– What are your network requirements?– What is your expected budget for this project?– Is the ROI greater than acquisition costs?– What will best fit your larger business continuity

strategy?

Best Practice

The Luxury Sedan: Disk-to-Disk Remote Copy

• Key advantages– Operates at the disk level – Can be (not always) less complex to set up and administer

than host-based approaches– Can offer the benefit of capturing all application changes. . .

• Key Disadvantages: Costly– Lacks transaction knowledge or what the data represents– Can be wasteful of network bandwidth if not properly set up– If operating in synchronous mode, can degrade application

performance

The Rising Alternative: Block-and-File Replication

• Fundamentals – Makes comparisons and only copies changes (at disk or file level)

• Key Advantages– Can be less expensive– Can be flexible to replicate all enterprise data regardless of disk

system– Copies only the most important files/data– Many-to-one replication architectures available– Limits amount of data transferred, reducing network load and cost

• Key Disadvantages– Isn’t 100% availability of data

Warning

Block and File Replication Details You need to Consider

File WAN Replication

Block WAN Replication

• Less expensive, host-based (or array-based) file and block replication

• Specific to storage vendor, OS or file system

Database Replication

• Typically done by replicating or mirroring log files• A number of variations:

– Continuous Mirroring: updates DBMS as changes(adds, updates, deletes) occur

– Change Data Capture: captures DBMS changes and stores them until a predetermined replication time

– Full Copy Refresh: replicates entire DBMS copy to target systems (done to resynchronize DBMS after outage)

• Trigger-based native DBMS is not usually appropriate for DR because of high system and network overhead

Snapshots: The Hotshots of Backup

• Establishes a separate identifiable storage entity and run operations against it– Primary purpose: backup, testing, conversion and batch

process

• Is dependent on OS, host and array support…• Advantage: it takes up less network bandwidth than

mirroring• Disadvantage: resynchronization of data is an art

– If you do not resynchronize, you must build snapshot mirror totally from scratch

New Kid on the Block: Virtualization and Disaster

Recovery• Virtualization software offers a new alternative– Data replication (over both IP and Fibre Channel) – Snapshot – High Availability Fail-over– A cost-effective approach to disaster recovery

• Key Challenges – Recreating the virtualization system can be difficult– Specifying file level information for replication can be difficult– Still a relatively new technology, so test well – Research virtualization players thoroughly

• Ask hard questions about number of customers doing this• How are issues of network performance and security handled?

Warning

Prioritizing Data: Integrating Mirroring or Replication to Your

Strategy

Amount OfData

Recovery Time

DelayedImmediate

LessMore

More

Less

Importance Of Data

Hot SiteRemote Disk Mirroring

Data Replication

Campus Disk Mirroring

Snapshot

Electronic Vaulting

Tape Onsite

Tape-Backup Offsite

Tool

OK, Now What? It’s The Network, Stupid

• Long-distance Remote Mirroring/Replication requires significant network integration– Mission: Connecting two or more islands of storage – Could be SANs, hot sites, remote disk or tape

• Myriad of network transport choices boil down to two fundamentals (from the POP out)– Fibre– IP

• Where to Start: Evaluate Network Requirements – Ask storage vendors for requirements– Map that to service provider bandwidth services

Specific Network Challenges for Remote Mirroring and

Replication• Enterprise network performance is many times slower than storage performance

• Things You Could Consider– What tools do the remote mirroring/replication vendor provide for

performance on a Metro SAN?• Network throttling – adjusting data amounts sent over wire• Compression – compressing data to take up less network bandwidth• Time-stamping – marking data at time saved or accessed

– Latency isn’t your friend• Measurable time it takes for an I/O transaction to reach destination• Distance is a factor – especially when extending data native limit• Storage traffic requires high bandwidth, low latency connections not typical of IP

Tip

Metro SAN Puzzle Pieces

Headquarters

Remote Site

PrimaryDisk Storage

RemoteDisk Storage

RemoteTape Library

Mirroring/Replication Software

Edge of Network Equipment (Director, Router or DWDM)

Service Provider Connectivity Services

Key Features

ATM, T3/E3, OC3+or Fibre Optic (DWDM)

Metro SAN Network Transport Options

Network Protocol

Performance Length of Distance

ESCON Full performance (200-M bits/sec. unidirectional)

8 km for full performance, 50% performance @ 20 km

FICON Bi-directional channel protocol, runs over at 1.063 G bit/sec.

100 km distance limitation

Dark Fibre Dedicated Fibre (depends on transport)

10 km without long-wave transceivers

iSCSI, iFCP, FCIP Still in proof-of-concept stage, but promise of 1 TB per hour over IP

Depends on applications, service, connection points – FCIP - primary for Metro SANs

DWDM - Gigabit (Optical) Ethernet (Most common)

Requires high-speed IP network to connect storage islands, OC3 or <

Depends on applications, service, connection points and routers used (DWDM)

Key Features

IP Network Options

• Private Router Backbones– Leased, dedicated lines– Optimized for performance (racing the sun)

• xSP VPNs– Customer purchases edge routers and ISP provides shared

backbone– Leverages Multiprotocol Layer Switching (MPLS) for

better Quality of Service

• Internet . . .– Not a disaster recovery tactic I would trust

Tips To Consider When Speaking With Your Service

Provider• Ask your xSP to provide you what their expertise is in storage services– Consider how you could leverage your existing connectivity services to

establish a cost-effective service contract for your backup services– Ask for a latency/network performance SLA– Your primary xSP should have partners to assist with storage services if

they don’t

• Consider leveraging storage vendor relationships to find service providers that can do integration

• Do or have done a network analysis to determine requirements for your backup services

• Determine if outsourcing is an option

Checklist

Metro SAN Challenges: Things You Need to Ask about

IP• Latency and Bandwidth • Security• Complexity• Quality of Service (QoS)• Dropped Packets• Manageability• NOTE: IP storage switch vendors are trying to

solve these things – so gauge them based on this

Checklist

Does Outsourcing Make Sense?

• Determine if outsourcing disaster recovery services for Data Mirroring and Replication services– Do I have the skills, personnel and infrastructure?

• Outsourcing provides a number of advantages– Enables enterprise to focus on core competence– Speeds IT’s ability to maintain and return to business operations– Leverages expertise and more plentiful specialized resources– Offers mirrored solutions for immediate recovery– Provides problem resolution expertise that speeds delivery of

services related to backup, security and performance monitoring– Delivers professional services to assist in design of a customized

business continuity plan

Best Practice

Ask for Help From a Professional . . .

• This is a complex proposition• Storage vendors will assist with best backup

technologies• Service Providers will offer options for services• Integrators with storage and networking practices

are best candidates for additional implementation– they are still rare in the world

Evaluate ROI for Disaster Recovery

• Come up with a ROI calculation for your data protection strategy

• Guidelines to remember– Calculated over three-year term– The higher the ROI, the more favorable the project– TCO vs. ROI – ROI wins out

• Key factors to be included in ROI analysis– Costs: downtime, personnel, assets– Reliability: data replication, mirroring, backups– System performance: how is systems and software utilized– Calculate savings: improved performance, revenue,

processes

Best Practice

Conclusions

• Don’t forget the fundamental goal: Disaster Recovery• Consider your options for mirroring/replication and

make a metric to measure them by– ROI analysis is one way of measuring options

• Be cautious of new technologies– New IP storage networking technologies and software offer

new options – but you need to be savvy in deployment

• There’s not one solution – strategize on ways to prioritize your data protection

Questions?

Jamie Gruener jgruener@yankeegroup.com