Hitch Hikers Guide to High Availability
Warwick RuddMicrosoft Certified Master (MCM) – SQL 2008Principal Consultant
[email protected]@Warwick_Rudd
About Me : Warwick Rudd
• SQL Server Consultant• MCM – SQL Server 2008• MCSM – Data Platform• Certified Trainer• Reviewed 4 SQL Server 2012 Beta
Exams• Blogger on Simpletalk.com• Presenter at:• User Groups• SQLSaturdays• TechED Australia
Contents
What is High Availability
Determining a High Availability Solution
High Availability Technologies
Examples of High Availability Environments
What is High Availability
“A system design approach associated service implementation that ensures a prearranged level of operational performance will be met during a
contractual measurement period”
“The principal goal of a high availability solution is
to minimize or mitigate the impact of downtime”
Downtime
Scheduled
DB Maintenance
Failover
Patching
System Configuration
Un-Scheduled
Failover
Hardware Failures
Loss of Network Connectivity
Power Outages
DowntimeAvalability % Downtime / Day
HH:MM:SSDowntime / MonthHH:MM:SS
Downtime / YearHH:MM:SS
90 144:00:00 73:02:55 876:34:55
99 00:14:23 07:18:17 87:39:29
99.9 00:01:26 00:43:49 08:45:56
99.99 00:00:08 00:04:22 00:52:35
99.999 00:00:00.86 00:00:263 00:05:15
99.9999 00:00:00.087 00:00:026 00:00:32
Determining a High Availability Solution
9’s Downtime
Recovery Point Objective (RPO)
Recovery Time Objective (RTO)
Recovery Level Objective (RLO)
High Availability Technologies
Non SQL
WSFC
FCI
Virtualisation
SAN Replication
SQL
Database Mirroring
Database Replication
Transaction Log Shipping
SMB & CSV Support
Availability Groups
High Availability Environment Factors
9’s Downtime
Recovery Objectives
Technologies
Cost $$$$$$$
Testing / Monitoring
Potential High Availability Environments
Stand-alone
Virtual Machine
WSFC
Log Shipping
Replication
Mirroring
Combined
VM & Mirroring
VM & Log Shipping
VM & Replication
WSFC & Mirroring
WSFC & Log Shipping
WSFC & Replication
Availability Groups
High Availability CapabilitiesHA Solution RPO RTO Automat
ic Failover
Readable Secondaries
AlwaysOn Availability Group (Synchronous Commit)
Zero Seconds Yes 0 - 2
AlwaysOn Availability Group (Synchronous Commit)
Seconds Minutes No 0 - 4
AlwaysOn Failover Clustered Instance NA Seconds - Minutes
Yes NA
Database Mirroring (High Safety) Zero Seconds Yes NA
Database Mirroring (High Performance) Seconds Minutes No NA
Log Shipping Minutes Minutes - Hours No Not During a restore
Replication Seconds Minutes - Hours No Yes
Virtual Machine NA Seconds - Minutes
Yes NA
Summary
What is High Availability
Determining a High Availability Solution
High Availability Technologies
Examples of High Availability Environments
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