7 Must-Know Disaster Recovery Strategies
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Transcript of 7 Must-Know Disaster Recovery Strategies
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