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| Toll Free: +44 800 088 5522 When Cluster Continuous Replication in Exchange 2010 Fails in Disaster Recovery!
MS Exchange is considered as one of the most reliable server environment to be used in almost all small and large establishments. However, if not prone to corruption issues they are also not immune to them. So it is likely that database files may get corrupt due to some reasons and mainly because of limited in-built precautions against damage issues in EDB files of server database. Prior to versions 2007 the disaster recovery feature employed is too less in number, which results in less availability of servers and hence low data accessibility.
To avoid such situations continuous efforts have been made to increase the level of security by building advanced disaster recovery features. Cluster Continuous Replication in Exchange 2010 is one such characteristic built to increase server availability. But the problem is that sometimes it also fails and at such situations it gets necessary to retrieve database mailboxes. Moreover the DAG service in release 2010 that includes cluster continuous replication is also complex in nature.
Know Cluster Continuous Replication in Brief
It is a feature provided for high availability of server and was introduced in Exchange 2007 and is a combination of asynchronous log shipping and replay technology. It marks its importance by the advantageous and matchless quality of service that it provides. It is said that it does not leave even a single chance of failure in Exchange disaster recovery. It uses the replication function to enable continuous and asynchronous updating of a secondary copy of database while alterations are done to the primary mailbox. So even if the main mailbox gets damaged, its content is available on the secondary.
Know the Working of CCR Characteristic
In CCR the replication capacities are integrated with the Cluster service to provide an apt solution for availability of server all the time avoiding all downtime issues. During installation of the passive node in a CCR environment, each storage group as well as its database is copied from the active node to the passive node. This procedure is called seeding and it provides a bottom line of the database for creating replicas. Once the first seeding is performed, replay and log copying are then performed continuously.
Disaster Recovery Features In Different Exchange Versions
1. Version 2003 and lower Exchange releases – MS Cluster Services (MSCS) is the only disaster recovery feature included in the several releases that came before ES 2007 and has quite too many limitations. Hence availability of server and data accessibility is very less. This is because MSCS provides redundancy at the hardware level only and not at storage level. If the active cluster node becomes unavailable all of a sudden, the Exchange Virtual Server (EVS) and any relevant cluster resources failover to the passive node and the end users are able to continue with their work.
Limitation – The drawback here is that the storage subsystem fails. In order to achieve recovery at the storage level, organizations are enforced to spend large amount in external applications that provide replication solutions. So, developers at Microsoft stepped ahead to build up strong recovery utilities in newer releases of the server environment.
2. Exchange 2007 – To enhance the recovery feature as well as to provide better precaution techniques, features such as Local Continuous Replication (LCR) and Cluster Continuous Replication (CCR) have been introduced. LCR targets small organizations CCR is built for medium and large organizations. Later on Standby Continuous Replication (SCR) with Exchange 2007 SP1 was introduced targeting at organizations of almost every size. All three features use a new asynchronous replication technology that works by shipping log files to a passive copy of storage group. After inspection it replays these into a passive copy.
Limiting Boundary – However, here also the disaster recovery features are not developed to the extent that can keep damage issues at bay.
3. Exchange 2010 – Since then continuous efforts have been made to enhance Cluster Continuous Replication in Exchange 2010, the failure recovery feature. Here, LCR and SCC have been removed whereas CCR and SCR have been integrated into Database Availability Group, popularly known as DAG which acts as the basic component.
Constraint – With ES 2010, the one and only in-built method to protect mailboxes database is by using DAG but sometimes it too fails.
CCR in Exchange 2010 Failed – Next What?
Cluster Continuous Replication in Exchange 2010 DAG, the enhanced and advanced in-built utility sometimes fails in recovering database mailboxes at times. At such times it really gets important to adopt some disaster recovery tool to get accessibility to data. At such situations Exchange Recovery, an external utility comes to the rescue by retrieving mailboxes to Outlook PST or even live server environment.
