To stay competitive in today's business climate, organizations must find ways to meet their business needs while controlling IT costs. IT departments face flat budgets and, at the same time, find that their organizations have become increasingly dependent on uninterrupted access to business-critical data. In today's world, prudent IT administrators prepare to recover from two types of disasters as part of a complete Business Continuity and Availability (BC and A) plan.
HP StorageWorks 3 Data Center Replication
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Table of contents Executive summary............................................................................................................................... 3 The HP StorageWorks 3 Data Center Replication solution......................................................................... 4 HP StorageWorks XP Continuous Access Synchronous ............................................................................. 5 HP StorageWorks XP Continuous Access Asynchronous ........................................................................... 6 HP StorageWorks XP Continuous Access Journal ..................................................................................... 8 Recovery point objective..................................................................................................................... 10 RPO equal to 0.............................................................................................................................. 10 RPO greater than 0 ........................................................................................................................ 10 Recovery time objective ...................................................................................................................... 10 RTO between one and five minutes .................................................................................................. 10 RTO of one hour or more ................................................................................................................ 10 The prior Multi-Site Disaster Tolerant Solution (MSDT)............................................................................. 11 3DC with HP StorageWorks XP Continuous Access Journal configurations................................................ 12 Comparing cascading and multi-target configurations ........................................................................ 13 Detailed rules and restrictions for 3DC configurations ............................................................................ 15 HP StorageWorks XP Continuous Access Journal and mirror unit descriptors ......................................... 15 A volume can only have one source ................................................................................................. 18 Replication pairs independent of each other...................................................................................... 20 Suspending a downstream link before the upstream link goes out of order............................................ 21 3DC failover and failback actions without a third link ............................................................................ 23 Action 1: Transition from a cascaded to multi-target configuration........................................................ 25 Action 2: Transition from a multi-target to cascaded configuration........................................................ 26 Action 3: Cascaded configuration data center failure......................................................................... 27 Failback to DC1 after a cascaded configuration failover..................................................................... 28 Action 4: Multi-target configuration data center failure ....................................................................... 29 Failback to DC1 after a multi-target configuration failover to DC2........................................................ 30 Action 5: Multiple data center failures .............................................................................................. 31 Failback to DC1 after a multiple DC failure ....................................................................................... 32 The benefits of the optional third data link ............................................................................................ 37 Action 6: Using the optional third link............................................................................................... 39 Recovery after the use of the optional third data link........................................................................... 43 Other configuration options ................................................................................................................ 50 4DC configuration ........................................................................................................................ [download for more]
