Database handiness group is the most important characteristic that has been made available in Exchange 2010 which addresses many of the restrictions of the high handiness characteristic that were available with old versions of exchange. This study provides an overview of DAG
1 ) Introduction about Microsoft exchange waiter 2010
– Microsoft exchange 2010 has been available from the 2nd period of 2009. It wholly redefines the Exchange waiter messaging platform and right up front, you should cognize that Exchange Server 2010 does off with the constructs of storage groups, Local Continuous Replication ( LCR ) , Single Copy Clusters ( SCC ) and clustered letter box waiters.
– In exchange waiter 2010, databases are no longer associated with storage groups. For letter box databases, Database Availability Groups can now be used to group database for high handiness and mailbox database are managed at the organisation degree alternatively of at the waiter degree. For public booklet databases, databases direction has been moved to the organisation degree but the functionality has non changed since it was implemented in Exchange Server 2007.
– Exchange waiter 2010 integrates high handiness into the nucleus architecture by uniting bunch uninterrupted reproduction ( CCR ) and standby Continuous reproduction ( SCR ) into a individual high handiness solution for both on-site and off-site informations reproduction. Exchange waiter 2010 besides adds automatic failure and recovery of any exchange waiter function when you deploy multiple exchange waiters. Because of these alterations, constructing a high handiness solution no longer requires cluster hardware or advanced bunch constellation.
– As you get started with exchange waiter 2010, you should concentrate on these:
+ How exchange waiter 2010 works with your hardware
+ what is a new characteristic of MS Exchange waiter 2010?
+ What is the Data Availability Groups ( DAG ) in MS exchange waiter 2010?
+ How does it work with Data Availability Group ( DAG ) ?
2 ) What is a new characteristic of MS Exchange 2010?
– Exchange waiter 2007 used LCR, SCC, CCR and SCR for high handiness and site resiliency of the letter box databases. In LCR, the database is replicated to another disc on the same waiter. If any hardware failure occurs, the letter boxs will non be available, as the reproduction of the mail databases are stored in the same hardware but different are stored in shared thrusts. Since SCC uses shared thrusts to hive away the letter box database, the failure of the waiter will guarantee that letter boxs are available as the other node of the bunch is still available. If any failure of the shared thrust occurs, the letter box available will be affected. CCR is a clustered letter box constellation which allows for hardware every bit good as storage redundancy. The restriction of CCR is that the bunch can incorporate merely two members, one active and one inactive node. Exchange 2007 SP1 introduced a new characteristic called SCR by which the databases from the primary site can be replicated to disater recovery sites and achieve site resiliency.
– Database handiness group ( DAG ) is the most important characteristic that has made available in exchange 2010 which addresses many of the restrictions of the high handiness characteristics that were available with old versions of exchange. The CCR which is used for onsite reproduction and SCR used for offsite reproduction has been combined together to organize DAG in exchange 2010. all the high available characteristics which were available in the earlier versions has been replaced by DAG Microsoft defines DAG as a group of up to 16 letter box waiters that host a set of databases and supply automatic database-level recovery from failure that consequence single databases. Any waiter in this group can host mailbox databases from any other waiters which are in the same database handiness group. This ensures the handiness of the letter box database in instance of hardware failure of a waiter or a storage failure.
3. Making DAG
– A database handiness group can be created by utilizing either exchange 2010 direction console or by utilizing bid Lashkar-e-Taiba and the letter box waiters can be added to the group. The active databases are replicated to the other waiters who are members of DAG. Network compaction and encoding are enabled for log file copying every bit good as seeding the database to other waiters in DAG. Making a separate web for the database reproduction and log file transportation is advised as this can use considerable web bandwidth even with the compaction enabled and can take to the clogging of the web.
– When a DAG is created, a DAG object is created in Active directory and an IP reference is assigned to it. As the waiter is added to the DAG, the waiter & A ; acirc ; ˆ™s name is added to the DAG object in Active directory.
4. High handiness and site resiliency with DAG:
– Unlike exchange 2007, where Windowss failover constellating has to make for puting up CCRs or SCCa, the failover bunch is created when the first waiter is added to DAG. DAG uses subset of Windowss failover bunch viz. cluster pulse, bunch web and bunch database. The fail over between the members waiters of DAG is managed by a procedure called is Active director which runs on every member waiter in DAG.
– The waiters from different subset can besides be added to the DAG. This enables the waiters from datacenters of different sites being members of the DAG. The site resiliency which was achieved by utilizing SCRs in exchange 2007 SP1 can easy be accomplished by utilizing this characteristic. The public booklet databases can non utilize the DAG
5. Client connexions:
– All MAPI clients linking to interchange 2010 letter box waiter connects through the CAS waiter. A new service called Exchange RPC service in CAS waiters handles all MAPI connexions. The client entree function determines which server presently hosts the active transcript of a letter box by mention to the DAG information. This is held Active Directory, and airt client when a databases has been switched.
Key alterations in exchange 2010:
To recognize the architecture demand of DAG in exchange 2010, the letter box databases have been associated to the organisational degree from the waiter degree. Besides, the storage groups have been removed and database names have to be alone across the organisation. The failover occurs at the database degree and non the waiter degree as old version. This helps in cut downing the failover clip well. Unlike exchange 2007 bunchs, multiple functions can be installed on the waiters who are member of DAG
6 ) Decision
– With the new Database Availability group functionality in Exchange Server 2010, you now have the ability to make high handiness solution on the Mailbox Server degree, and this functionality replaces the Continuous Cluster Replication ( CCR ) and Stan-by Continuous Cluster Replication ( SCR ) in Exchange Server 2007. The Database Availability Group is what CCR/SCR should hold been. It is flexible, powerful and less complex than the CCR/SCR solution and it combines the best of both universes. I truly recommend that everybody should be start and seek MS exchange with Database Availability Group and whether possible and implement for the company.
7. Acronyms Used in the study:
– LCC: local uninterrupted reproduction
– CCR: bunch uninterrupted reproduction
– SCC: individual transcript bunch
– Dekagram: database handiness group
– Ad: Active directory