Exchange 2013 Haute disponibilité et tolérance aux sinistres (Session 1/2 première partie)


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Attention, Session en Anglais. Attention Session en 2 parties. Ceci est la première partie. Cette session sera animée par Scott Schnoll, Senior Content Developer chez Microsoft Corp et veritable Gourou Exchange. La messagerie est un élément ultra critique du système d'information : Elle ne DOIT PAS tomber. Pour cela, Exchange 2013 intègre les toutes dernières technologies en terme de tolérance de panne et de haute disponibilité. Scott Schnoll vous expliquera la mécanique de l'intérieur ! Cette session vous donne accès à l'état de l'art sur Exchange. C'est LA session à suivre pour découvrir la mécanique de haute disponibilité d'Exchange 2013.

Speaker : Scott Schnoll (Microsoft)

Published in: Technology
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Exchange 2013 Haute disponibilité et tolérance aux sinistres (Session 1/2 première partie)

  1. 1. Exchange Server 2013 High Availability and Site Resilience (1/2) Scott Schnoll Senior Content Developer Microsoft Corporation Twitter: @Schnoll Infrastructure, communication & collaboration
  2. 2. Agenda – Part 1 • Database Availability Group Internals • Witness Server #mstechdays Infrastructure, communication & collaboration
  3. 3. Agenda – Part 2 (16:30-17:15, salle 253) • Dynamic quorum • DAG member maintenance #mstechdays Infrastructure, communication & collaboration
  4. 4. DATABASE AVAILABILITY GROUP INTERNALS #mstechdays Infrastructure, communication & collaboration
  5. 5. DAG Internals • • • • • Microsoft Exchange Replication service Active Manager Client component Microsoft DAG Management service Cluster service and components Windows Crimson Channel #mstechdays Infrastructure, communication & collaboration
  6. 6. DAG Replication Service • Introduced in Exchange 2007 RTM – Microsoft Exchange Replication service | MSExchangeRepl – MSExchangeRepl.exe – Required on all Mailbox servers (not just DAG members) – Communicates with Active Directory and other DAG members #mstechdays Infrastructure, communication & collaboration
  7. 7. DAG Replication Service • Includes 16 components Active Directory lookup Copy status lookup Replay core manager Seed manager Autoreseed manager • Disk reclaimer manager • Replay RPC server wrapper • Remote data provider wrapper • • • • • #mstechdays • Active Manager • Active Manager RPC server wrapper • Failure item manager • TPR API manager • Support API manager • Server locator manager • Health state tracker • VSS Writer Infrastructure, communication & collaboration
  8. 8. Active Manager Client Component • Runs inside client access and transport services – Microsoft Exchange RPC Client Access MSExchangeRPC – Microsoft Exchange Transport – MSExchangeTransport – Microsoft Exchange Frontend Transport – MSExchangeFrontendTransport – Client Access Front End (CAFÉ) components #mstechdays Infrastructure, communication & collaboration
  9. 9. Active Manager Client Component • When connecting clients or routing messages, client access and transport services query Active Directory and Active Manager to find out location of the active copy of a mailbox – DAG members with Standby Active Manager (SAM) role respond to these queries #mstechdays Infrastructure, communication & collaboration
  10. 10. DAG Management Service • Introduced in Exchange 2013 CU2 – Microsoft Exchange DAG Management service | MSExchangeDagMgmt – MSExchangeDagMgmt.exe – Runs on all Mailbox servers (not just DAG members) – Communicates with Active Directory and other DAG members • Includes 4 components – – – – #mstechdays Active Directory lookup Copy status lookup Monitoring Tracer instance Infrastructure, communication & collaboration
  11. 11. DAG Management Service • Created for two primary reasons: – so the Replication service can have more focused functionality – so Managed Availability actions can kill lower-priority activities • Logs events in same place as Replication service • Other functions will move to this service – AutoReseed, Disk reclaimer, Dynamic replay lag playdown #mstechdays Infrastructure, communication & collaboration – Future AutoDAG copy layout and mobility features
  12. 12. Cluster service • Introduced in NT Server Enterprise Edition (1997) – Cluster Service | ClusSvc – Clussvc.exe • Exchange DAGs use several cluster components – Membership and node management – Networks and heartbeating – Quorum #mstechdays Infrastructure, communication & collaboration
  13. 13. Cluster service • Quorum is required in order to mount databases • Quorum is based on votes, not membership • Voting can be rigged – Votes can be taken away manually or dynamically • Exchange manages quorum model, not quorum – Exchange management of quorum model based on nodes, not votes – Removing votes requires manual configuration of quorum model – Exchange will make incorrect quorum model management decisions if votes are manually removed at the cluster level #mstechdays Infrastructure, communication & collaboration
  14. 14. Cluster registry • Active Manager stores database / server information in the cluster registry for DAG members – Registry changes are replicated immediately to all DAG members • Stored information is used as part of BCSS #mstechdays Infrastructure, communication & collaboration
  15. 15. Cluster registry • ActiveServer – Name of server where database is currently mounted or expected to be mounted when mount operation completes • LastMountServer – Name of server where database was last successfully mounted • LastMountedTime – Date and time stamp of the last time database was mounted #mstechdays Infrastructure, communication & collaboration
  16. 16. Cluster registry • MountStatus – Current mount status for database (mounted / dismounted) • IsAdminDismounted – Designates whether current dismounted status is the result of administrator action (true / false) • IsAutomaticActionsAllowed – Designates whether the database can be automatically activated (true / false) #mstechdays Infrastructure, communication & collaboration
  17. 17. Crimson Channel • Applications and Services logs – Area of Windows Server event log used by applications for logging and internal communication – These logs store events from a single application or component rather than events that might have system-wide impact – This is referred to as an application's crimson channel • Exchange 2013 has a crimson channel with multiple areas – – – – – – #mstechdays ActiveMonitoring HighAvailability MailboxDatabaseFailureItems ManagedAvailability PushNotifications TroubleshootersInfrastructure, communication & collaboration
  18. 18. #mstechdays Infrastructure, communication & collaboration
  19. 19. WITNESS SERVER AND WITNESS SERVER PLACEMENT #mstechdays Infrastructure, communication & collaboration
  20. 20. Witness Server • A server that participates in a failover cluster with an even number of members – Is not a member of the cluster/DAG – Does not contain a copy of quorum data • File share on this server is represented by File Share Witness resource in cluster core resource group – Uses IsAlive check for availability #mstechdays Infrastructure, communication & collaboration
  21. 21. Witness Server • File Share Witness Resource Behavior – If server or share are not available, cluster resources are failed and moved to another node – If FSW resource does not come back online, it remains in a Failed state, with restart attempts every 60 minutes – If witness server needed for quorum, and resource cannot be brought online, quorum will be lost • Single restart attempt for FSW resource in Failed state #mstechdays Infrastructure, communication & collaboration
  22. 22. Witness Server • When witness server is needed to maintain quorum, one of the nodes locks the witness.log on witness server – Node that locks witness.log file is called the locking node – If enough nodes are in contact with the locking node to constitute a majority, quorum is maintained – Nodes that can’t communicate with locking node lose quorum #mstechdays Infrastructure, communication & collaboration
  23. 23. Witness Server • Attempts to lock witness.log file occur in a specific order – Node that owns cluster core resource group tries immediately – Nodes not owning cluster core resources wait 6 seconds before trying #mstechdays Infrastructure, communication & collaboration
  24. 24. Witness Server •Cluster Core Resources •Sequence #: 20 22 21 •Lock witness.log •Sequence #: 21 •Sequence #: 20 22 Challenging node attempts witness lock. Lock already exists – sequence # higher, challenge not successful. Cluster state change – node owning cluster core resources locks FSW – updates sequence number 0 #mstechdays 1 2 3 4 5 6 7 8 9 10 11 Infrastructure, communication & collaboration 12 All nodes available. FSW lock released. Changes replicated, sequence numbers in sync. 13 14 15 16
  25. 25. Witness Server •Sequence #: 22 •Cluster Core Resources •Sequence #: 20 •Lock witness.log •Sequence #: 21 •Sequence #: 20 •Cluster Core Resources •Sequence #: 21 22 Cluster state change – node owning cluster core resources unavailable. 0 #mstechdays 1 2 3 4 5 Challenging node attempts witness lock. No lock exists, lock successful, sequence number updated. 6 7 8 9 10 11 Infrastructure, communication & collaboration All nodes available. FSW lock released. Changes replicated, sequence numbers in sync. 12 13 14 15 16
  26. 26. Witness Server Placement • Exchange 2010 guidance – “We recommend that you use a Hub Transport server running on Exchange Server 2010 in the Active Directory site containing the DAG. This allows the witness server/directory to remain under the control and visibility of an Exchange administrator.” – “If your DAG is extended to multiple datacenters, we recommend deploying the witness server in the datacenter considered to be the primary datacenter.” #mstechdays Infrastructure, communication & collaboration
  27. 27. Witness Server Placement • Exchange 2013 guidance more complicated due to options introduced by architectural changes • Exchange 2013 includes support for new DAG configuration options – A third location, such as a third physical datacenter or branch office • Ultimately, the placement of a DAG’s witness server depends on your business #mstechdays requirements and the options available to you Infrastructure, communication & collaboration
  28. 28. Witness Server Placement Deployment scenario Placement Recommendation Single DAG deployed in one datacenter Locate witness server in the same datacenter as DAG members Single DAG deployed across two datacenters; no additional locations available Locate witness server in primary datacenter Multiple DAGs deployed in one datacenter Locate witness server in the same datacenter as DAG members. Additional options include: • Using the same witness server for multiple DAGs • Using a DAG member to act as a witness server for a different DAG Multiple DAGs deployed across two datacenters Locate witness server in the same datacenter as DAG members. Additional options include: • Using the same witness server for multiple DAGs • Using a DAG member to act as a witness server for a different DAG Single or Multiple DAGs deployed across more than two datacenters Locate the witness server in the datacenter where you want the majority of quorum votes to exist #mstechdays Infrastructure, communication & collaboration
  29. 29. Witness Server Placement • If your organization has a 3rd location, a witness server can be deployed there for automatic database failover between two other sites – The witness server location must have network infrastructure and connectivity that is isolated from network failures that affect the two datacenters with DAG members • For all DAGs, the availability of the witness server should be on the Exchange #mstechdays Infrastructure, communication & collaboration
  30. 30. Witness Server Placement • IaaS providers and cloud providers are not supported for use as a witness server – This includes Windows Azure, which does not yet support the required underlying network configuration to allow an Azure file server VM to act as a witness server in a multi-datacenter deployment – More info at #mstechdays Infrastructure, communication & collaboration
  31. 31. Related Content • Exchange 2013 Haute disponibilité et tolérance aux sinistres (Session 2/2 première partie) – 12/02/14 - 16:30-17:15, salle 253 • Exchange 2013 Dimensionnement et Performance – 12/02/14 – 17:45-18:30, salle 252B #mstechdays Infrastructure, communication & collaboration
  32. 32. QUESTIONS? Thank You! #mstechdays Infrastructure, communication & collaboration