How To Check AlwaysOn Auto Failover
Jun 7, 2015
I Config Ha-Alwayson on 2 test servers . In addition, was defined a listener for them.i can connect to them from the listener and in directly. I did manual Failover and it worked.However all connection to all servers (primary and secondary and listener) was breaked. I expected my connection To The listener, be stable. But How can I test the Auto failover mechanism? I run this scenario :
1- I filled all free space from the primary server else a bit.
2- And run on it a Huge Update to fill remain free space.
3- MeanWhile I Run an insert command into listener IP. (in a while Loop)
I expected :
>>> After run update or in middle of it , The primary server face to a problem. (Full Log file). And This was happened.
>>> After I expected The Failover act and change Primary And Secondary.And My insert commands Continues without Break Or Continue On new server After some Seconds
But It didn't Happend.Both Of 2 Command are stoped !!!!! And auto failover didnt act. I tryed To create a manual fail on primary server . I Tried to Offline the main database in primary server.
Then
1- What is the meaning Of fail that Auto failover act about it ?
2- In which scenario I can Test It ?
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Oct 29, 2015
1. Once fail over to secondary replica, what will happen to connected session in primary node? can the session fail over to secondary seamlessly or need to re-login. what happen committed transactions which has not write to disk.
2. Assume I have always on cluster with three nodes, if primary fails, how second node make write/ read mode.
3. after fail over done to 2nd secondary node what mode in production(readonly or read write).
4. how to rollback to production primary ,will change data in secondary will get updated in primary.
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Oct 29, 2015
1. In alwaysON fail over cluster, Once fail over to secondary replica, what will happen to connected session in primary node? can the session fail over to secondary seamlessly or need to re-login. what happen committed transactions which has not write to disk.
2. Assume I have always on cluster with three nodes, if primary fails, how second node make write/ read mode.
3. After fail over done to 2nd secondary node what mode in production(readonly or read write).
4. How to rollback to production primary ,will change data in secondary will get updated in primary.
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Dec 10, 2014
I have setup SQL AlwaysOn between primary and DR data centers. Here is the setup:
Primary data center: Server1 (Primary), Server2 (Sync Commit Secondary), Server3 (ASync Commit Secondary)
DR data center: Server4 (ASync Commit Secondary)
Data synchronization and manual failover works fine. But, sometimes, the AlwaysOn cluster automatically fails over to Sync Commit Secondary on Primary data center. Here is the error message from Failover Cluster Manager->Cluster Events:
"Cluster has missed two consecutive heartbeats for the local endpoint xx.xx.xx.yy:~3343~ connected to remote endpoint xx.xx.xx.zz:~3343~"
"Cluster has lost the UDP connection from local endpoint xx.xx.xx.yy:~3343~ connected to remote endpoint xx.xx.xx.zz:~3343~"
I had our network engineer check all connections multiple times and he confirmed everything is fine. But he was also able to confirm (using monitoring tools) that right at the time of a failover, there is almost 2GB worth of traffic going from Primary Server to DR server. That happens every time. I had checked the times of all failovers and there is no job or process occuring that will produce 2GB worth of data. Also, this happens regardless of which server is primary.
Even though the failover works fine, this unexpected automatic failover due to missed heartbeats are occurring often (2-3 times a month).
Here is the list of errors from the Cluster Validation Report:
Under Network Section, I see the following error messages in Red:
Validate Network Communication
Network interfaces Server4 (DR) - SAN_Team and Server1 (Primary) - SAN_Team - VLAN 20 are on the same cluster network, yet address xx.xx.xx.pp is not reachable from xx.xx.xx.yy using UDP on port 3343.
Network interfaces Server4 (DR) - SAN_Team and Server2 (Secondary) - SAN_Team - VLAN 20 are on the same cluster network, yet address xx.xx.xx.qq is not reachable from xx.xx.xx.yy using UDP on port 3343.
[Code] ....
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Jan 27, 2015
So I have 2 servers S1 & S2.
Database Group 1 = L1 with Primary S1 and Secondary S2
Database Group 2 = L2 with Primary S2 and Secondary S1
For 99% of the time the 2 groups of databases are not related. For the 1 procedure that does move data from L1 to L2 something like
Update L2.DB.Owner.Table
set flag = 1
Whare a = 0
On S1 I have a linkedServer with connection to L2.
If I have a failover I cannot have L2 on S2 as they are essentially the same server.
How to I use the 2 groups hand in hand.
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Jun 30, 2015
I have a 3 node 2014 AlwaysOn setup. The primary and secondary are set for automatic failover. The third node, of course, is manual (until 2016). The 2 nodes with are automatic are sitting in one datacenter, the third is in another. If the first datacenter was to go down, I would manually have to failover to the third node? What's the normal process here for having two datacenters and ensuring the availability group is always available?
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Jun 30, 2015
we have to build high availability SQL 2012 cluster for VDI and we have two options. One option is to build a server cluster with combination of failover and mirroring and other option is to build failover cluster with AlwaysOn.We are not sure which option to chose. We have contacted Microsoft support to provide us some documents and instructions for failovermirroring combination but they have send us instructions for AlwaysOn option.
What would be best way to build high availability cluster for VDI? Also, since first option is very complicated.
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Apr 3, 2014
I'm looking for a solution to have cross data center automatic failover in the event of a data center loss for highly critical databases. I would like to have local HA and also automatic failover to the DR site. This does not seem possible with AlwaysOn.
Is my only option for automatic cross data center failover to build a node in one data center and a node in the other data center with a node/FS at a third data center in order to maintain quorum? I'd like to have local HA in the mix but that doesn't seem possible.What pattern for the highest data security and also availability?
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Jun 16, 2014
If there is a history kept somewhere of failover events of a database in an AO group? I have 2 replicas with automatic failover and I'm looking for a history of failovers.
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Oct 6, 2014
We are implementing a multi-site (Windows Server Failover Cluster) WSFC to enable Always On between our primary and DR site. We are not going to use SQL clustered instances. We are not planning to use shared disks. Each node is running a standalone instance of SQL 2012.
I have successfully configured a 3 node multi-site Windows failover cluster with no shared storage. For quorum, I have defined a File Share Witness (FSW). The FSW has voting rights and is in the DR site. The setup looks like this –
WSFC –
•Node A – Site #1 (voting right = 1)
•Node B – Site #1 (voting right = 1)
•Node C – Site #2 (voting right = 0)
•FSW – Site #2 (voting right = 1)
Again - There are no shared disks in our setup. We are not going to use SQL clustered instance. We are going to use Always On with these 3 nodes.
SQL Always On –
•Node A – Site #1 (Primary Replica)
•Node B – Site #1 (Readable Secondary)
•Node C – Site #2 (Readable Secondary)
All the setup including the “availability group” works properly under this setup. However, a failover to site #2 under DR situation is not working and I know why but don’t know what needs to be done to fix the problem.
The following works fine –
•Automatic failover between nodes A and B (same site – site #1)
•Forced failover to node C in site #2 provided at least one of the nodes in site #1 is up (non – DR situation) - this will ensure the cluster is up
The following is not working –
•Forced failover to node C in site #3 when both nodes in site #1 are lost (true DR situation) – This is because the cluster is not up at this point.
I know I have to bring the cluster up somehow and I have not been able to do so by restarting the cluster service.
I tried to run the command to start cluster service.
Question –
How can I FORCE the cluster to come up in Site #2 on node C when it has no voting rights?
I have always worked with even number of nodes and shared disks with traditional clustering. I am not sure what needs to be done in this scenario with 3 nodes and a FSW.
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Sep 30, 2015
How can we find the cluster failover count in always on ?
As my AG is configured as synchronous mode , AG went offline and we manually restarted the AG service when we check the properties on AG role they r in default setting ?
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Oct 27, 2015
An automatic failover set exists. This set consists of a primary replica and a secondary replica (the automatic failover target) that are both configured for synchronous-commit mode and set to AUTOMATIC failover.Configured the both AG Group database automatic failover and synchronous-commit mode.But automatic Failover failed also Cluster service not started automatically at Node2. It got connected through AO Listerner after starting Node1. As below SQL Error log during shutdown Node1
Date,Source,Severity,Message
10/27/2015 10:44:20,spid37s,Unknown,AlwaysOn Availability Groups: Waiting for local Windows Server Failover Clustering node to come online. This is an informational message only. No user action is required.
10/27/2015 10:44:20,spid37s,Unknown,AlwaysOn Availability Groups: Local Windows Server Failover Clustering node started.
[code]....
what need to be change existing AO configuration?
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Mar 28, 2014
What happens when an automatic failover occurs, in a two server AlwaysOn Availability Group configuration, where the secondary replica is configured as read-only?
Will it only allow read-only connections, or will it become read-write and can accept INSERT, UPDATES and DELETES when assigned the new role as Primary?
Is it correct that adding a third server/node, that just acts as passive and should be used for automatic failover, to support true HADR, would NOT need another license .. and that licenses would only be required for the previous Primary and Secondary (Read-Only) replicas?
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Jul 27, 2015
Is there any single TSQL query which provides below info.When did my AlwaysOn Availability group failed over and from which node it failed to which new node(i.e. replica)?
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May 22, 2015
I'm getting an error adding Replica to SQL AlwaysOn failover cluster in the new availability group wizard. When I enter the name of the target node (secondary replica) server and press connect, I get the following:
A network-related or instance-specific error occurred while establishing a connection to SQL Server.
The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 2) The system cannot fine the file specified
The SQL Browser service is up and running on the target. I am using an Azure VM for my SQL instance. This cluster spans geographies from our on-premise site to Azure via a VPN. This is a multi-subnet cluster. I'm attempting to create a new AG from the primary replica node and the target is a node on Azure called SSASNodeAz03.
[URL]
Full error:
Connect to Server
Cannot connect to ssasnodeaz03
Additional information: A network-related or instance-specific error occurred while establishing a connection to SQL Server.
The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 2) The system cannot fine the file specified
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Oct 23, 2015
We had to failover our primary db server for maintenance to our secondary replica. The primary was rebooted during maintenance. We failed back after the maintenance and one of the databases is not synchronizing.
I checked sys.dm_hadr_database_replica_states, and it is showing that it is INITIALIZING.
It has been in this state for more than 45 mins now. The last_sent_time, last_received_time, last_hardened_time and last-redone_time are all stuck with a time stamp 45 mins ago.
They haven't changed. How do i resume this database and bring it back in sync?
I tried suspending and resuming the data movement, but hasn't worked.
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Aug 25, 2015
I am running SQL 2014 2-node AlwaysON Availability groups, Enterprise Edition in our environment and 5 databases are part of AG.
Question is, sometimes AG is getting failed over to node2 but always our preferred node is node1 due to some business needs otherwise some of our jobs will fail.
So, what I looking for is, a sql script which can handle a situation wherein, for some reason, AG is failed over to node2, it should be able to detect if node1 is back online or not and if so, it should fail back to node1. How to do this using tsql query or stored proc or sql agent job ?
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May 13, 2008
Hi all,
Is it possible to setup auto-autofailower on 2 servers? Do i need to setup a witness on each server or what?
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May 22, 2007
I have been looking over the forum, and also other sites for information about my problem but cant seem to find what im looking for so I have decided to make a quick post.
Presently, I have 3 computers setup for mirroring. One is the principal, another the mirror and the third is the witness.
Im using SQL 2005 Enterprise Edition on all three, and creation of the mirror using SQL Studio works without problems. Manual failover (using the button in SQL Studio) also works fine.
When I start the "Mirror Monitor" application, and connect to the two DB servers the status is all green, they are connected to each other and the witness server can be contacted.
Now here is my issue; when its time for an automatic failover situation (pulling the plug from the current principal for example) it detects the fault and changes the status of the mirror to "principal" BUT keeps the other status to "Disconnected" (Principal, Disconnected) so no active connections to the failed over database will work.
When running the mirror monitor during the failed fail-over attempt the still online database reports that the connection to the witness is still present but the mirror is offline.
There are a few error notices in the logs, but from what I can tell they are normal for whats happening. But the codes would be 1479 (cant talk to the database; this would be the one we took offline) and 1474 (network name is no longer available; once again as it was taken offline). Note that these errors are also in the witness server logs, as I believe one should expect.
Any help or assistance with this problem would be appreciated.
Thanks,
Sean
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Mar 12, 2015
I have a 2-node Windows Cluster and File Share Witness with an availability group. The cluster is set to sync and auto failover. I'm using SQL 2014 and Windows 2012R2. I'm trying to understand the steps to apply Windows Updates that require a restart. Are the steps something like this where ServerA is the primary replica and ServerB is the secondary replica.
Apply updates to ServerB.
Restart ServerB.
Fail ServerA availability group to ServerB using ALTER AVAILABILITY GROUP MyAvailGroup FAILOVER;. Server B is now the primary.
Apply updates to ServerA.
Restart ServerA.
Fail ServerB availability group to ServerA using ALTER AVAILABILITY GROUP MyAvailGroup FAILOVER;. Server A is now the primary.
What I don't understand is where Drain Roles on the Failover Cluster Manager fits in?
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Apr 9, 2015
We have 2 data centers, site 1 and site 2. Site 1 is generally our primary, and site 2 is our Disaster Recovery (DR) site. I want to setup a SQL instance to have extremely high availability. Therefore I was looking at using DB mirroring, with synchronous data writing, high-safety and auto-failover. This requires the usage of a witness server.My problem with this setup, is that if the witness and principal are both at site 1, if site 1 goes away (power failure, asteroid impact, lol, anything else that would be a *true* DR scenario), then there is no failover to the mirror server at site 2. However, if you put the witness at site 2, anytime the WAN link between site 1 and site 2 has an issue, the DB will auto-failover to site 2. Is the reason for the recommendation of the witness being at the primary site because the thinking is that WAN link failure is likely more common than a *true* DR scenario that takes out all of site 1?
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Dec 15, 2014
how to check the errors when a database is configured in Always on in sql 2012?
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Aug 17, 2015
We have a requirement to build SQL environment which will give us local high availability and disaster recovery to second site. We have two sites- Site A & Site B. We are planning to have two nodes at Site A and 2 nodes at Site B. All four nodes will be part of same Windows failover cluster. We will build two SQL Cluster, InstanceA will be clustered between the nodes at Site A Server and InstanceB will be clustered between the nodes at Site B, we will enable Always On Between the InstanceA and InstanceB and will be primary owner where data will be written on InstanceA and will be replicated to InstaceB. URL....Now we want we will have instanceC on the Site B and data will be writen from the application available on Site B, will be replicated to the instance on the Site A as replica.
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Mar 3, 2007
We have set up Mirroring with a witness server and everything works fine when we failover from the SQL Management console.
However, if we failover when our Maccola client is connected, the client blows up - clearly because it can no longer connect to the database.
The ODBC DSN used by the Maccola client shows a checkbox for the 'select a failover server' but the checkbox is grayed out.
Also the summary of settings for the DSN at the end of the wizard reveals that the failover to server (y/N) option is set to N.
The default setting for this DSN is 'populate the remaining values by querying the server' but it doesn't appear to be getting the settings for failover from the server or any other interactive DSN settings either. The server is clearly set for mirroring.
Another suspicious item is that the DSN cannot connect to the server with SA permissions, even though the server is set to mixed security and we use the correct authentication.
Is it possible that the client MACHINE is not authenticating with the domain or sql server properly. We are logged into the client with the domain account that is the SQL admin account on the sql server box.
We should be able to interact with the sql server settings through the ODBC DSN on the client shoulnd't we?
Are we missing a service pack on the client?
Thanks,
Kimball
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Feb 16, 2014
Since upgrading from SQL Server Management Studio 2008 R2, I've noticed that it no longer autosaves queries that have not been manually saved first. If a file has been manually saved the autorecover files end up in the following directory:
%appdata%MicrosoftSQL Server Management Studio11.0AutoRecoverDatSolution1
However, I have ended up in the situation where I have unsaved queries when my computer has crashed and have not been able to recover them.
I have also found references to .sql files stored in temp files in the following directory, but the files here seem to be very haphazardly caught:
%userprofile%AppDataLocalTemp
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Jan 23, 2004
I have an MS SQL Server table with a Job Number field I need this field to start at a certain number then auto increment from there. Is there a way to do this programatically or within MSDE?
Thanks, Justin.
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May 20, 2015
I have multiple ODBC connection and how to check all connection automatically during routine check by using batch file.
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Jan 27, 2015
how to remove always on in sql 2012 ?
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Aug 18, 2014
How to find the pending transactions to be applied on secondary in Always On? Can i get those details from dashboard?
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Oct 22, 2014
We are looking to setup an AlwaysOn A/G between two SQL instances across two SQL clusters - one cluster has two nodes the other has three nodes.
Is this possible using WSFC? Does the A/G wizard just handle this?
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May 14, 2015
is there any limition in AlwayOn to add database in secondary replica?
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May 13, 2013
I'm setting up my first pair of Sql 2012 servers using AlwaysOn. I set up backups to run on the primary and I understand that you can set up backups to run on both the primary and secondary servers but the secondary will fail. Is there a way I can stop the secondary server from sending out error messages about failed backups? Is it possible to script it so that the server looks at whether it's primary or secondary and turns on or off alerts based on that?
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Mar 13, 2014
I am trying to build the 2 node 2 clusters with the AlwaysOn.
Here isthe landscape.
2 nodes PROD failover cluster (running once instance)
2 nodes DR failover cluster (running 2 instances - DR and PRE-PROD)
Both clusters are in different geographies.
PRE-PROD can be editable. So out of scope of Always On.
One instance on PROD -> DR of the other box. [Want to achive thru AlwaysON]
Now my Question:
1) Do i need to have all the 4 nodes in same failover cluster group? If yes, then this would become MultiSubnet cluster Or Is there any way those 2 diffrerent failover clusters (one DR and one PROD) can be part of AlwaysOn.
2) Can i use the clustered disks as in the above landscape for always on?
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