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Saturday, May 11, 2013

Recoverpoint- Back to Basics


Recoverpoint beginners post!

Data replication can be performed on the host, storage and network level. Recoverpoint (RP) allows us to do the Network-Based replication through which we can host resources can be preserved for applications and also supports heterogeneous storage arrays with lower cost.

Recover Point objective (RPO): Point-in-time (PIT) data must be recovered to after outage, implicitly measures the amount of data you are willing to loose.



Recover Time objective (RTO): The time it takes to fully recover to the RPO, in other words it defines the maximum amount of time that systems may be unavailable.

RP Configurations:
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Continuous Data Protection (CDP): It is a synchronous product that mirrors SAN volumes in real time between one or more arrays at a local site by maintaining a history journal of all changes that can be used to rol back the mirrors at any PIT.

Continuous Remote Replication (CRR): It provides bi-directional, heterogenous block-level replication across any distance using asynchronous, synchronous, and snapshot technologies using IP networks and asynchronous over FC. It periodically distributes updates to the remote copy of the data with all changes that occurred on the local copy since the last update.

Concurrent Local and Remote replication (CLR): It provides both CDP and CRR for the same volume.

Recoverpoint Appliance (RPA): It is the data protection controller for RP. RPA's are deployed in a two-to-sixteen node cluster configuration that allows active-active failover between the nodes.

RP Volume (Repository): 
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a. Created on existing storage array
b. Repository contains:
-Configuration information
-Consistency group metadata
-Data also maintained on RPA's on both sites
c. Visible to RPA's only (Zoned and masked to the RPA's)
d. 1 per cluster
e. Min size 3 GB and Max 4 GB

Journal Volumes:
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An additional volume is dedicated on the storage at both sites for the purpose of holding images waiting to be distributed. Each consistency group has either two or three journals: one or two at source side, and one at the target side.

Journal Volume Sizing
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Journal Size = [(data per second) * (required rollback time in seconds) / (1 - target side log size)] x 1.05

20% of the journal must be reserved for the target side log
5% for internal system needs

Example:
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24 hour rollback requirements (86400 seconds)
5Mbps of new data writes to the replication volumes in a consistency group

Mbps x rollback time in seconds ((5*86400)/(1-0.2))*1.05 = 56700 Mb
Convert Mb to GB (56700/8)/1000 = 70.875 (71GB)

Note: The snapshots will be striped across the multiple journal volumes which increases the performance of the journal volumes. So its important to have same sized journal volumes.

Replication Set: A production volume and its associated volume at the local replica, the remote replica, or both.

Note: The replica volumes of the replication set should be the same size of the production source volume.

RP Splitters:
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a. Host splitter (Kutils)
b. Fabric splitter (Cisco SANTap, Brocade)
c. Storage array splitter (recommended)

Consistency Group (CG):
====================
a. Contains all related replication sets
b. Contains one journal volume per copy
c. Contains replication policy information

Group Sets: Grouping of consistency groups to which the system applies parallel bookmarks at a user defined frequency.

-Useful for CG's that are dependent on one another or that must work as a single unit (ex: db & log files)
-The automatic periodic bookmark includes name of the group set, ID number

Splitter Zoning: The storage array splitters must have access to the RPAs for both reading and writing. Zone all RPA HBA ports with all storage array ports.






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