Table of Contents
What is always on SQL Server 2016?
AlwaysOn feature is now an included in SQL Server 2016 Standard Edition, but it is referred to as AlwaysOn BAG. It is created and managed similarly to AG, but AlwaysOn BAG is capable to only use a subset of features compared to the more advanced AlwaysOn AG on SQL Server Enterprise Edition.
What is always on feature in SQL Server?
The Always On availability groups feature is a high-availability and disaster-recovery solution that provides an enterprise-level alternative to database mirroring. Introduced in SQL Server 2012 (11. x), Always On availability groups maximizes the availability of a set of user databases for an enterprise.
What is difference between AlwaysOn and AlwaysOn clustering?
An SQL AlwaysOn failover cluster instance provides high availability and disaster recovery at the SQL Server level. AlwaysOn Availability Groups (AAG) provide high availability and disaster recovery at SQL database level.
Does SQL Server 2016 Standard support always on?
An Always On basic availability group can be created on any two SQL Server 2016 Standard Edition servers.
What is the purpose of AlwaysOn availability groups?
Always On availability groups provide high availability, disaster recovery, and read-scale balancing. These availability groups require a cluster manager. In Windows, the failover clustering feature provides the cluster manager. In Linux, you can use Pacemaker.
What are some advantages of using AlwaysOn feature?
The following are some of the features and benefits of using AlwaysOn:
- Combined HA / DR.
- Zero Data Loss Protection.
- Failover of Multiple Databases.
- Automatic or Manual Failover.
- Local or Shared Storage.
- Automatic Page Repair.
- Active Use of Secondaries.
- Enhanced Performance.
What are the prerequisites for AlwaysOn in SQL Server?
Prerequisites for Installing SQL Server AlwaysOn
- Windows Server 2008 R2. Windows Server 2008R2 is the minimum Windows Server edition allowed for deploying AlwaysOn.
- Windows Server Failover Cluster.
- .Net 3.5.1 or greater.
- Windows hotfixes.
- Windows Domain.
- No domain controller.
- Windows Firewall.
- Sufficient Disk Space.
What is the difference between database mirroring and AlwaysOn availability groups?
Essentially you had to choose between using database mirroring for disaster recovery (asynchronous) or for high availability(synchronous). AlwaysOn, however, allows up to two synchronous replicas and two asynchronous replicas to be simultaneously active.
How many databases can I put on one SQL Server?
32,767
For SQL Server, the max number of databases you can have on a single SQL Server instance is 32,767.
How many AlwaysOn availability groups can be configured in always on?
You can have more than one AlwaysOn Availability Group on your instance, but databases cannot belong to more than one group. Not configured for database mirroring.
What is the maximum database size in SQL Server 2016?
Database Engine objects
| SQL Server Database Engine object | Maximum values for SQL Server (64-bit) |
|---|---|
| Files per database | 32,767 |
| File size (data) | 16 terabytes |
| File size (log) | 2 terabytes |
| Data files for memory-optimized data per database | 4,096 in SQL Server 2014 (12.x). The limit is less strict on SQL Server 2016 (13.x) and later. |
How many columns can exist together per table?
Database Engine objects
| SQL Server Database Engine object | Maximum values for SQL Server (64-bit) |
|---|---|
| Columns per table | 1,024 |
| Columns per UPDATE statement | 4,096 |
| Columns per view | 1,024 |
| Connections per client | Maximum value of configured connections |
What is pool size in SQL Server?
A connection pool is created for each unique connection string. When a pool is created, multiple connection objects are created and added to the pool so that the minimum pool size requirement is satisfied. Connections are added to the pool as needed, up to the maximum pool size specified (100 is the default).
How many records can SQL Server hold?
Row Size Limits. The maximum row size for a given table is determined by several factors: The internal representation of a MySQL table has a maximum row size limit of 65,535 bytes, even if the storage engine is capable of supporting larger rows.
How many requests can a SQL Server handle?
By default, SQL Server allows a maximum of 32767 concurrent connections which is the maximum number of users that can simultaneously log in to the SQL server instance.
What are AlwaysOn basic availability groups in SQL Server 2016?
As database mirroring is deprecated, SQL Server 2016 introduces AlwaysOn Basic Availability Groups, offered as a database mirroring replacement, offering a similar feature profile.
Does AlwaysOn AG require shared disk storage?
AlwaysOn Availability Groups. AlwaysOn AG does not require shared disk storage for the server hosting the SQL Server. This SQL Server high availability technology has been an Enterprise feature. This means you cannot configure SQL Server Standard Edition to use AlwaysOn AG with versions prior to SQL Server 2016.
What is AlwaysOn solution in SQL Server?
Solution. SQL Server AlwaysOn is a marketing term which refers to the high availability and disaster recovery solution introduced when SQL Server 2012 was launched. To be more specific, SQL Server AlwaysOn consists of two technologies: AlwaysOn Failover Clustering Instances (AlwaysOn FCI)
Can SQL Server AlwaysOn be implemented on physical systems?
Can be implemented on physical SQL Server systems, or on SQL Server systems that are running as virtual machines Whenever SQL Server AlwaysOn is mentioned, it is not specific because it can refer to either AlwaysOn FCI or AlwaysOn AG.