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High Availability and Disaster Recovery Topologies

Damien McAullayOracle Fusion MiddlewareJune 2014

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Business Continuity Planning (BCP)

• How to make your business “life” go on in the case of a disaster– It’s about the business, not the means– Does not necessarily incorporate IT• (but usually does in the 21st century)

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Disaster recovery

• The “IT” part of BCP

• How do I recover my data, configurations, …?• Where do I restore my data to?• How can my users get access to the

recovered environments?

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Some data recovery strategies

Take periodic backups to local media, store media offsite

Replicate data to another site

Backup directly to offsite Replicate data to the cloud

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High availabilityDowntime per year

90% (one nine) 36.5 days

99% (two) 3.65 days

99.9% 8.76 hours

99.99% 52.56 minutes

99.999% 5.26 minutes

99.9999% 31.5 seconds

99.99999% 3.15 seconds

• Determined by “up time”– (total time – down time) / total time

• Target availability often expressed in class of “nines”

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High availability

• Often practical to pre-define downtime (e.g. maintenance windows, periods where users are not active like public holidays)

• Three key aspects:– No single points of failure– Reliable switching mechanism(s)– Capability to detect failure, recover/bypass, and alert technician

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WebLogic

Example scenario: WebLogic web-based application, database, and internal/external users

WLS

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Eliminate SPOF

Add 2nd WebLogic server to cluster

Add a 2nd WebLogic node to cluster

Add 2nd Database server

Add load balancers to distribute load across WLS and DB

WLS WLSWLS WLS

LB

LB

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Reliable switching

Use a network load-balancer (e.g. F5 or CSM) to distribute requests across WLS

Use Active GridLink data source in WLS to connect to RAC Database (clustered)

WLS WLSWLS WLS

RAC

F5

ActiveGridlink

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Monitoring, recovery, and alertingUse OEM to monitor WLS/DB, push metrics into service desk platform

Use OEM/scripts to remediate common/known problems (e.g. restart WLS on OOM)

Add notifications for outages, performance degradation, etc. to technicians

WLS WLSWLS WLS

RAC

F5

Ora

cle

Ente

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e M

anag

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Your

Ser

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Des

k Pl

atfor

m

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Fast disaster recovery

WLS WLSWLS WLS

RAC

DC1

WLS WLSWLS WLS

RAC

DC2

WLS WLSWLS WLS

RAC

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Maintenance• Server patching

1.0 1.1

• Deploying app updates

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Closing advice …• Change Control– Make sure you can identify the current “state” of your deployments

• Practice makes perfect– The more often you rebuild your environments, the better you’ll perform on race day– Private-cloud-style provisioning and CI encourage practices useful for DR

• Don’t reinvent the wheel– Use the Oracle Maximum Availability Architectures as a starting point

• Start with your BCP– HA/DR is not cheap, so don’t do anything unnecessary

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