80a disaster recovery

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  • KDB: This information really belongs in the earlier deck on volumes in the mirroring section, but the information is not there, so I put it here.
  • 80a disaster recovery

    1. 1. Disaster Recovery 7/6/2012© 2012 MapR Technologies Disaster Recovery 1
    2. 2. Disaster Recovery Agenda • Definitions & Considerations • Disaster Preparation • Exercise: Create a Dump File • Exercise: Create a Remote Mirror • Cluster Restoration • Exercise: Restore from a Dump File • Exercise: Copy Read-Only Data • Final Thoughts© 2012 MapR Technologies Disaster Recovery 2
    3. 3. Disaster Recovery Objectives At the end of this module you will be able to: • Describe the important considerations involved in disaster recovery • Identify the different approaches to disaster recovery • Explain how to prepare for a disaster • Create a dump file and remote mirror • Describe the different ways of recovering from a disaster • Restore data from a dump file© 2012 MapR Technologies Disaster Recovery 3
    4. 4. Definitions & Considerations© 2012 MapR Technologies Disaster Recovery 4
    5. 5. What is Disaster Recovery?  Disaster Recovery is a large and complex topic – You must consider a variety of objectives and tradeoffs that involve complex business and technical issues – This presentation is not a tutorial on Disaster Recovery  One key aspect of Disaster Recovery is preservation of data – If one data center is lost, we need to ensure that there is a consistent copy of the data available elsewhere in order to restore service – MapR provides a solution to this problem using volume mirroring • Data can be dumped to local storage and managed manually, or • One cluster can replicate its data to another cluster automatically© 2012 MapR Technologies Disaster Recovery 5
    6. 6. Considerations  When designing your DR solution you must take into account two key factors – RPO – Recovery Point Objective • Essentially this is how much data you are prepared to lose in a disaster • This impacts how frequently you update the backup – RTO – Recovery Time Objective • This defines how quickly you want to restore service after a disaster • Lower RTOs imply more automation and often pre-built backup systems  There are two fundamental tradeoffs you must consider – An operational cluster for recovery vs. manual rebuild – Mirror dumps to local storage vs. automatic mirroring© 2012 MapR Technologies Disaster Recovery 6
    7. 7. Cluster Recovery Approaches  Your primary cluster is gone for whatever reason. You need to restore service elsewhere  Option #1: have an available and running cluster already prepared – RTO will be relatively low – of course data has to be restored first  Option #2: create a new cluster when needed – RTO will be significantly higher© 2012 MapR Technologies Disaster Recovery 7
    8. 8. Data Mirroring Approaches  Option #1: dump volumes – Dumps of course need to be moved off site – After a disaster, obtain dumps and manually restore to cluster • Note that if you have done incremental mirror dumps to reduce the size of the dumps, multiple dumps will have to be restored for each volume – Places less demand on network but • Has high manual operational cost • RTO is likely very high – RPO can also involve significant data loss depending on how frequently you move data off site  Option #2: Mirror to a remote cluster – Frequency of incrementals is configurable  frequency implies your RPO – Restoration may require copying data from read only to read/write volume – Requires operational cluster as target of mirrors© 2012 MapR Technologies Disaster Recovery 8
    9. 9. Mirroring Key Behaviors  Mirror data is pulled by the destination cluster  Destination/mirror volume is read only  Mirrors are snapshot based and thus time consistent – Meaning that the replica mirror will have an exact copy of the data that was present at the time of the mirror start – There is no danger of one file being changed while the mirror is occurring  Mirroring operation is smart enough to only replicate what has changed since the last mirroring operation – At the block level - changing one byte of a 1TB file triggers an 8K update, not 1TB  Data is compressed on the wire when transmitting  Mirroring consumes significant network bandwidth over the WAN – More network capacity improves rate you can mirror and thus RPO – Plan taking into account data change rates and network bandwidth© 2012 MapR Technologies Disaster Recovery 9
    10. 10. Disaster Preparation© 2012 MapR Technologies Disaster Recovery 10
    11. 11. Preparation – no backup cluster  Execute initial backup by dumping volume  Move dump files to remote location  Execute periodic dumps and move off site  Dumps can be full or incremental  Incremental dumps are faster but complicate restore© 2012 MapR Technologies Disaster Recovery 11
    12. 12. Preparation – active backup cluster  Create mirror volume on backup cluster  Execute initial backup by dumping volume or initiate mirroring  If the volume is large relative to network bandwidth, a dump is likely a better choice  Restore dump files to mirror volume if needed  Commence remote scheduled mirroring  If network bandwidth is scarce you can dump locally and restore manually at other site© 2012 MapR Technologies Disaster Recovery 12
    13. 13. Exercise: Create a Dump File© 2012 MapR Technologies Disaster Recovery 13
    14. 14. Exercise: Create a Dump File  Full dump: maprcli volume dump create -name volume -dumpfile name -e statefile1  Incremental dump maprcli volume dump create -s statefile1 -e statefile2 -name volume -dumpfile name  Note: you can limit the number of incremental dumps by using different statefiles© 2012 MapR Technologies Disaster Recovery 14
    15. 15. Exercise: Create a Remote Mirror© 2012 MapR Technologies Disaster Recovery 15
    16. 16. Exercise: Create a Remote Mirror  Create Mirror (on backup cluster): maprcli volume create -name volume_mirror -source volume@cluster –type 1  Initiate mirroring: maprcli volume mirror start –name volume_mirror© 2012 MapR Technologies Disaster Recovery 16
    17. 17. Cluster Restoration© 2012 MapR Technologies Disaster Recovery 17
    18. 18. Restoration  X Build the cluster if needed  Use offsite dumps or read only mirrors as data source  Restore data to the cluster  Activate cluster operations – schedule jobs, inform users, update dependent systems, etc.© 2012 MapR Technologies Disaster Recovery 18
    19. 19. Restoration from Dump Files  Restore dump files to new mirror volumes  Restore each incremental dump!  If volumes need to be writable  Create volumes to receive data  Copy data from mirror volumes© 2012 MapR Technologies Disaster Recovery 19
    20. 20. Restoration from Remote Mirrors  Data is already there!  If not mounted, you can just mount the mirrors  If volumes need to be writable  Create volumes to receive data  Copy data from mirror volumes© 2012 MapR Technologies Disaster Recovery 20
    21. 21. Exercise: Restore from a Dump File© 2012 MapR Technologies Disaster Recovery 21
    22. 22. Exercise: Restore from a Dump File  Full dump: maprcli volume dump restore -dumpfile name -name volume_mirror –n  Incremental dump maprcli volume dump restore -dumpfile name -name volume_mirror© 2012 MapR Technologies Disaster Recovery 22
    23. 23. Exercise: Copy Read-Only Data© 2012 MapR Technologies Disaster Recovery 23
    24. 24. Exercise: Copy Read-Only Data  Mount mirror maprcli volume mount –name volume_mirror -path pathToRO  Create Read/Write Volume: maprcli volume create -name volume -mount 1 -path pathToRW  Copy data using NFS cp –r -p /mapr/cluster/pathToRO /mapr/cluster/pathToRW© 2012 MapR Technologies Disaster Recovery 24
    25. 25. Final Thoughts© 2012 MapR Technologies Disaster Recovery 25
    26. 26. Final Thoughts  Active cluster with mirroring – best RPO and RTO – Faster mirroring -> more network bandwidth but more currency (better RPO) – Full initial dump useful if lots of data already in primary cluster • Sneaker net to backup cluster – Incremental dumps with sneaker net appropriate if bandwidth constrained  Manual dumps with offsite storage – RPO and RTO will be worse – Frequency of incremental dumps defines RPO – Full vs. incremental dumps • Full consume significantly more storage space and are slower • Incremental will take significantly longer to restore© 2012 MapR Technologies Disaster Recovery 26
    27. 27. Questions© 2012 MapR Technologies Disaster Recovery 27

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