SPN for Availability group(AG) listener for SQL Server 2016

Requesting some inputs..

We have a 2 node SQL 2016 Availability group configured and apps currently use primary replica for connection. We are now planning to use listener instead. Questions is, how to make sure we are using kerberos authentication for application connectiions?. Is it mandatory to manually register SPN for the listener? or is it automatically created?. is this a one time activity?. How to make sure SPN is registered automatically for the listener when the AG restarts or failover to second node?. Appreciate all the responses.

How to configure Oracle traffic director for full site failover to have high availability?

I have two server system, each server having both apache tomcat server(deployed web app) and oracle 11g database server. The database on the two server is synchronised by oracle data gaurd for high availibility. tomcat Web servers is running individually on each server system with no load balancing. One server acts as primary server and other server acts as redundant server.

Usually for any failure on primary server, I have to manually change the IP/Domain name to access the other server.

I have came across Oracle Traffic director which may solve my isssue to switch any client request to redundant server in case of failure of primary server. Since I am new to oracle traffic director, can any one guide me to configure otd for full site failover?

behavior of a Sql Server availability group listener and a jdbc client during a failover?

i have a question about the behavior of the AG listener during a failover… when the failover happens, I realize that all the connections on both primary and secondaries are closed.

if the client apps are using one of the blessed client libraries (such as microsoft jdbc > 6.0) they will then start immediately trying to reconnect to the ip addresses associated with the listener. But what happens during the 10 second period (or whatever it is) for the failover to complete? Might a client successfully get a connection, only to get a fatal error message when it tries to use it? Or is something done to ensure that no client will get a connection successfully during failover itself, so that that when a client does successfully get a connection, it is actually usable?

(Also, specifically for a java client using a recent microsoft jdbc driver, does it try only once per getConnection() call? Or will it keep polling until a logintimeout is hit?)

I realize i’m mixing questions about server behavior with client library behavior but I’m trying to understand the whole scenario; thanks.

Resource Hosting Subsystem was terminated which caused Availability group to fail

The following error was occurred in cluster events and the availability group was failed which resulted the databases in non-synchronizing state.

A component on the server did not respond in a timely fashion. This caused the cluster resource ‘AG’ (resource type ‘SQL Server Availability Group’, DLL ‘hadrres.dll’) to exceed its time-out threshold. As part of cluster health detection, recovery actions will be taken. The cluster will try to automatically recover by terminating and restarting the Resource Hosting Subsystem (RHS) process that is running this resource.

Please help me to find the root cause (A component on the server did not respond in a timely fashion).


Sync logins and Agent jobs across all replicas in Distributed Availability Group

I am using dba_CopyLogins stored proc to sync logins on replicas in Distributed Availability group , but the database level permissions are not transferred due to database sync operation is going on.. Is there any way to sync all logins and permissions from global primary to Forwarder and other replicas? also how to copy agent jobs?

How does Automatic Seeding work – Always On Availability Group

I found only these two statements from BOL regarding this Initial Data Synchronization method:

Link 1

Automatic seeding uses the log stream transport to stream the backup using VDI to the secondary replica for each database of the availability group using the configured endpoints.

Link 2

During automatic seeding, SQL Server performs a backup over the network for initialization.

Looking into SQL Server Error logs of both primary and secondary replicas, these two logs caught my attention:

On primary replica

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On secondary replica

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My question is related to the working nature of automatic seeding, namely where does taken backup is stored before restoring on the secondary replica?

Are availability groups required for AlwaysOn

Beginning a project to create an HA SQL server environment. We are limited to using SQL Server Standard edition, currently 2016. From what I have found, AO(AlwaysOn) for standard edition limits you to basic AG (availability group) and thus only 1 database per AG. This is going to be tough since most of our SQL instances contain 30+ databases. Can you implement AO without AGs? Are there other ways to configure AO to address our needs? All databases on any of our instances are managed similarly and thus wouldn’t need the flexibility that managing at an AG provides.