Ye Olde Cluster Curiosity Shoppe
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Mark Broadbent, a principal SQL consultant at SQLCloud, presents on the complexities of SQL Server clustering and failover setups. The document outlines several cluster configurations, their benefits, difficulties, and failures, highlighting the importance of understanding dependencies and the potential impacts of changes in a clustered environment. Key recommendations include thorough testing in a virtual lab and careful, informed decision-making to avoid unnecessary panic during operations.
Ye Olde Cluster Curiosity Shoppe
- 1. Ye Olde Cluster Curiosity Mark Broadbent Principal SQL Consultant SQLCloud SQLCLOUD.CO.UK Shoppe
- 2. About Mark Broadbent. “30 billion times more intelligent than a live mattress” Microsoft Certified Master: SQL Server Microsoft Data Platform MVP Owner/ Principal at SQLCloud Email: mark.broadbent@sqlcambs.org.uk Twitter: retracement Blog: http://tenbulls.co.uk Event Lead to the UK’s first ever SQLSaturday (Cambridge) and Cambridgeshire SQL Usergroup Event #4 on 8/ 9/ 10th Sept 2016 (pre-con/s) and (Community day) https://www.facebook.com/groups/sqlsaturdaycambridge/ http://sqlcambs.org.uk
- 3. Agenda The occasional demo fail The best part of the presentation… Beer O‘Clock Standalone versus Clustering Incredibly tenuous link between the Curiosity Shoppe and clustering! 1 4 2 5 Exhibits 3
- 5. Standalone deployment of SQL Server/s MSDTC Instance1 Instance2
- 6. Clustered deployment of SQL Server/s MSDTC Install (New) Install (add) Install (add) *1 MSDTC clustered deployment can vary greatly depending upon design considerations *1 Failover Cluster Instance1 Failover Cluster Instance2 Install (New) Install (add)Install (add)
- 8. Welcome to Ye Olde Cluster Curiosity Shoppe!
- 9. The Shrunken Head One physical node but one (or very small number of) instances that you would have otherwise deployed as standalone. Useful for easy expansion of HA infrastructure when budget allows and abstraction of network name Failover Cluster Instance1 10.0.0.15 sqlserver1 Cluster Role/ Group Windows Cluster is a single node only running a clustered instance
- 10. Port o’ Plenty Failover Cluster Instance1 Failover Cluster Instance2 Failover Clustered Instances can be executed to all listen under the default SQL Server listening port. This can provide various benefits (and potential negatives). Remember there can only be one default instance! Failover Cluster Instance3 Port 1433 Port 1433 Port 1433
- 11. The Bearded Lady Failover Cluster Instance1 Failover Cluster Instance2 Each node sees all storage Each instance brings more clustered disks. This can result in too many cumulative disks and become unmanageable.
- 12. Many Headed Cluster Failover Cluster Instance1 Failover Cluster Instance2 One to many (unused) SQL Failover Clustered instances. Excellent for pre-testing Cluster node upgrades and testing database upgrade prior to risking production Failover Clustered Instance. Failover Cluster Instance3 Failover Cluster Instance4
- 13. “Cutting off one head” – upgrading clustered instance Fail test clustered instance onto upgraded node to upgrade instance/ databases Apply latest service pack If upgrade fails we can uninstall patch or at worst case evict node and rebuilt/ reinstall SQL instances. Our production instances have suffered zero downtime from a failed deployment
- 14. The Zombie Failover Cluster Instance1 Failed Network Name causes dependent SQL Cluster Resource to fail. Forced online local service can return a temporary limited service 10.0.0.15 SQL Service Network Name Cluster Role/ Group Dependency Bring online
- 15. The Indestructible Network Name Active Directory in Windows 2008 and above has a protection property In Windows 2003 you would need to Deny the Everyone group for the Delete and Delete Subtree permissions Deleted objects can be recovered from Tombstone in some situations.
- 16. Demo Let’s do the Zombie!
- 17. The Marie Celeste Failover Cluster Instance1 Cluster Groups can be easily created with little to no risk to the cluster. They are great for testing storage and other clustered resources ahead of time. Cluster Group New Cluster Storage for Instance 1 Fail across all nodes
- 18. Montezuma’s Revenge Failover Cluster Instance1 10.0.0.15 Network Name Cluster Role/ Group Empty Cluster Role/ Group Accidental move drags the whole dependent freakin’ lot! Failover Cluster Instance1 10.0.0.15 Network Name
- 19. The Bodysnatcher Failover Cluster Instance1 Failed Clustered Instance across all nodes can spell panic (especially if the clustered set up is inherited). If the failure is serious and cannot be repaired a reinstallation on a new cluster can be attempted from old installation files. Cluster Role/ Group Install (New) Install (add) Install (add) New Cluster Role/ Group Install to nodes using reference files
- 20. Installation of Death! Failover Cluster Instance1 Cluster Role/ Group The Installation of SSIS has huge ramifications for a Cluster. What software and drivers will be required by packages? This is always a never ending moving set of goalposts and risk to Cluster stability. SSIS SSIS SSIS TNSnames.ora
- 21. The Stone Fish Failover Cluster Instance1 Failure to identify all dependencies to resource prior to its removal can cause the whole failover clustered instance to unexpectedly fail. Whoopsie! 10.0.0.15 Network Name Cluster Role/ Group “Hidden” or missed dependent to disk
- 22. In Summary… • Never attempt any operation on any cluster object *unless* you understand the impact. • Always validate anything you hear or read with your own testing in a virtual lab. • It is easy to make a mistake performing an operation or start to panic. Always take time to understand what you are doing and break it down into smaller steps if necessary. • It is worth repeating… DON’T PANIC!
- 23. Thank you for listening! Email: mark.broadbent@sqlcambs.org.uk Twitter: retracement Blog: http://tenbulls.co.uk