Download The Problem? - SQL Saturday

TOP 10 Availability Groups
Improvement in SQL 2016
Karol Papaj
10.12.2016
Thank you to our AWESOME sponsors!
10.12.2016
• Karol Papaj
• SolidQ
• SQL Server BI
• SQL Server High
Availability
• SQL Server Relational
Engine
• Based in Slovakia
• [email protected]
10
Workgroup
clusters
The Problems?
Active Directory
New-Cluster
–Name "DomainlessCluster"
-Node SQL1,SQL2
-AdministrativeAccessPoint DNS
-StaticAddress 192.168.14.120
Active Directory
Demo
Workgroup clusters
AG on workgroup clusters
Demo
SQL 2016 AG on
Workgroup clusters
Limitations
Windows
Server
2016
SQL
Server
2016
Kerbero
s
AvailabilityGr
oup
9
Basic HA in
Standard
Edition
The Problem?
Deprecated DB Mirroring
CREATE AVAILABILITY GROUP [StdAG]
WITH (BASIC)
FOR DATABASE [DB1]
…
Deprecated DB Mirroring
Source: https://www.brentozar.com/archive/2015/06/how-to-set-up-standard-edition-alwayson-availability-groups-insql-server-2016/
Deprecated DB Mirroring
Deprecated DB Mirroring
Limitations
2
replicas
1
DB
Listen
er
Backup
on
secondary
Read access
to
secondary
8
Group-managed
Service
Account
The Problem?
Password
Synchronization
*********
Automatic
SPN’s
registration
gM Service Account
New-ADServiceAccount
-Name gMSASqlService
-DNSHostName gMSASqlService.squ.com
-PrincipalsAllowedToRetrieveManagedPassword
SQLServers
Install-ADServiceAccount
gMSAsqlservice
Demo
Group-managed Service Account
7
Database
seeding
The Problem?
Backup/Restore
CREATE AVAILABILITY GROUP [SQLAG01]
FOR REPLICA ON
N'SQL3' WITH (
ENDPOINT_URL =
N'TCP://SQL3.SQU.COM:5022',
FAILOVER_MODE = AUTOMATIC,
AVAILABILITY_MODE = SYNCHRONOUS_COMMIT,
SEEDING_MODE=AUTOMATIC
),
N'SQL4' WITH (
ENDPOINT_URL =
N'TCP://SQL4.SQU.COM:5022',
FAILOVER_MODE = AUTOMATIC,
AVAILABILITY_MODE = SYNCHRONOUS_COMMIT,
SEEDING_MODE=AUTOMATIC
);
Backup/Restore
ALTER AVAILABILITY GROUP [SQLAG01]
JOIN
GO
ALTER AVAILABILITY GROUP [SQLAG01]
GRANT CREATE ANY DATABASE
GO
ALTER AVAILABILITY GROUP [SQLAG01]
ADD DATABASE DB1
GO
ALTER AVAILABILITY GROUP [SQLAG01]
ADD DATABASE DB2
GO
Demo
Database seeding
6
Load balancing
of read-only
replicas
The Problem?
Overloaded first
read-only
replica
Overloaded first read-only
replica
ALTER AVAILABILITY GROUP [SQLAG01]
MODIFY REPLICA ON N'SQL3'
WITH
(
PRIMARY_ROLE(READ_ONLY_ROUTING_LIST=( ('SQL5','SQL4‘ ),'SQL3'))
)
Demo
Load balancing of read-only
replicas
5
Scalability
The Problem?
Synchronization
Performance
The Problems?
Log transport
Context
switche
s
Compressio
n
Multiple
Log
Writers
Redo Speed
SQL
2012/2014
SQL 2016
SQL 2016 is > 5x
better in
log throughput
540
82
Before
SQL 2016
Source: https://blogs.msdn.microsoft.com/psssql/2016/04/28/sql-2016-it-just-runs-faster-alwayson-log-transportreduced-context-switches/
SQL 2016 > 2x better in
CPU Utilization
36
on secondary
17
Before
SQL 2016
Source: https://blogs.msdn.microsoft.com/psssql/2016/05/03/sql-2016-it-just-runs-faster-alwayson-parallelcompression-improved-algorithms/
4
AG failover
when
one db detected
as unhealthy
The Problem?
AG Health Detection
SQL 2014
AG Health Detection
SQL 2016
AG Health Detection
CREATE AVAILABILITY GROUP
[SQLAG01]
WITH (DB_FAILOVER = ON)
FOR DATABASE [DB1],[DB2]
…
AG Health Detection
Demo
AG failover when one db detected
as unhealthy
3
Increased # of
replicas as a
failover target
The Problem?
Failed first
secondary
replica
Primary replica
Secondary replica
Secondary replica
Demo
Increased # of replicas as a
failover target
2
DTC Support
Cross-instance Cross-database
The Problem?
Transaction
Integrity
SQL 2012 & 2014
Begin
Distributed Tx
Rollback
Failover
DTC
DTC
RscMgr #1
Standalone
?
RscMgr #2
RscMgr #3
Primary
Secondary
SQL 2016
Begin Distributed Tx
Commit
Failover
DTC
DTC
RscMgr #1
RscMgr #2
Standalone
RscMgr #2
Primary
Secondary
Transaction integrity
CREATE AVAILABILITY GROUP
[SQLAG01]
WITH (DTC_SUPPORT = PER_DB)
FOR DATABASE [DB1],[DB2]
…
Transaction integrity
Source: https://www.brentozar.com/archive/2015/06/how-to-set-up-standard-edition-alwayson-availability-groups-insql-server-2016/
Cross-instance Cross-database
1
Distributed AG
The Problem?
Replication
to remote DC
SQL 2012 & 2014
2X
3X
1X
Primary
Secondary
Secondary
Secondary
Secondary
Secondary
SQL 2016
1X
Primary
Primary
Secondary
Secondary
Secondary
Secondary
Secondary
Replication to Remote DC
ALTER AVAILABILITY
CREATE
AVAILABILITYGROUP
GROUP[SQLAG04]
[SQLAG04]
WITH (DISTRIBUTED)
JOIN
AVAILABILITY GROUP ON N'SQLAG02'
WITH(
LISTENER_URL = N'TCP://AG02Listener:5022',
FAILOVER_MODE = MANUAL,
AVAILABILITY_MODE = ASYNCHRONOUS_COMMIT,
SEEDING_MODE = AUTOMATIC
),
N'SQLAG05'
WITH
(
LISTENER_URL = N'TCP://AG05Listener:5022',
FAILOVER_MODE = MANUAL,
AVAILABILITY_MODE = ASYNCHRONOUS_COMMIT,
SEEDING_MODE = AUTOMATIC
);
Demo
Distributed AG
Limitations
Secondary
AG becomes
read-only
No automatic
failover
between AG’s
Questions?
10.12.2016
Thank you!
10.12.2016