If I have multiple servers in my AG group and set two of the secondaries to synchronous with auto failover, how do I control which one one of the two secondaries will become primary if the original primary goes down?We need to maintain HA even during patching so need a first choice auto failover and a second choice auto failover.
View 9 RepliesI have virtualbox installed on my notebook. For testing purpose, is it possible to setup SQL Server Fail-Over cluster using virtual box? I don't have a shared storage. How can I simulate that?
View 1 Replies View RelatedHow to create a SQL 2012 Failover cluster using VMs?
View 9 Replies View RelatedI have the following mirroing setup for DR.
Prinical(ServerA) and Mirror(ServerB)
When we do a DR test we do manual failover from Principal(ServerA) to Mirror(ServerB)
Now
ServerB is Prinicpal
ServerA is Mirror
Applications do their testing against the new principal which is ServerB but dont want to take those changes or sync to ServerA(Mirror).
Is there any way to do this without breaking the mirror?
Finally It will go back to original setup after the test which Server A is Principal and Server B will be its mirror.
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] ....
I am trying to create a failover cluster without the log shipping in 2012 as i've done it with a static instance with some database.Is the "AlwaysON" feature the solution when an application creates random and numerous databases within the instance and we need a failover scenario ?
View 9 Replies View RelatedSo 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.
what type of replication is best and easiest to startup on the DR site in event of a failover for an SQL server with very high transaction occurring on the database.I normally handle Oracle database and we use SAN to SAN replication to the DR site, all w have to do is mount the replicated disks at the DR site and Startup the database.How do i achieve this on SQL database including having the using logging details work at the DR site.
View 2 Replies View RelatedToday a vendor bluntly stated that VMWare provides the same failover and redundancy for SQL that would render "AlwaysOn" high availability unnecessary.
Essentially that VMWare would detect a problem and failover and have .9999 uptime .
I'm reading up on Always on and I am confused what is the difference between AlwaysOn Availability Groups and AlwaysOn Failover Cluster Instances.
View 3 Replies View RelatedI'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?
I had a cluster running on 3 nodes (windows failover cluster) with server 2012 and SQL server 2012 running in the cluster. Well, I thought I'd just go ahead and rename all 3 of the hosts with new hostnames and it apparently broke the cluster pretty bad. Now when I open failover cluster manager I cannot see anything nor can I connect to the cluster object in AD. I re-named all of the hosts back to their original names but that didn't work.
View 5 Replies View RelatedIf 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.
View 0 Replies View RelatedI have a cluster using Always on on 2012 and i have set up a Witness file share which losts connectivity the other day and a failover was invoked.
Is there a threshold i can change so that the cluster can try a couple of more times to connect before it fails over ?
I have 2 servers in a SQL Server Fail-Over Cluster. IOW I use always-on availability groups. I run backups - full, diff and log - regularly via SQL Agent on one server only depending on which is primary. If there is a fail-over, then backups will continue on the other server. If I have to restore a database in an availability group I probably would need some combination of full, diff, and log backups from each server. Would that actually work? I test the backups weekly however I just realized that I never tested that scenario.
View 1 Replies View RelatedWe 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.
Approach 1:
Prod - shared storage between server 1 and 2
Server1: clustered SQL instance with availability group as primary
Server2: Passive server for clustered instance of PROD
DR - shared storage between server 1 and 2
Server1: Clustered SQL instance with availability group as replica
Server2: Passive server for clustered instance of DR
Approach 2: Using replicated SAN
Prod -
Server 1: Standalone instance with availability group as Primary
Server 2:Standalone instance with availability group as replica
DR -
Server 1: Offline until Disk group 1 (Prod server 1) has been broken and brought online at DR
Server 2: Offline until Disk group 2 (Prod server 2) has been broken and brought online at DR
Both these approaches will work wont they? I have only built and played with normal availability groups across servers, not mixing it with clustered instance replicated SAN
how to resolve and trouble shoot the availability group is not ready for automatic failover in sql2012
View 4 Replies View RelatedLet's say I have a two node AG, Server A and Server B. Server A is normally the primary and Server B is the replica. Whenever the primary fails over from A to B or from B to A, I'd like to automatically run a script that will restart the SQL Agent service on the new replica.
View 3 Replies View RelatedHow 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 ?
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?
I am new to SQL Server 2012 clustering.I added a new instance to one of the two nodes.when I try to move it to the other node it fails.Do I need to install it on both?If so, what options do you install on the second node?
View 7 Replies View RelatedWhat 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?
I've setup a two node Cluster Server (non-shared storage) with a file sharing witness. I'm testing some of the different failover scenarios to see that everything is working properly. Everything works fine until I try testing the failure of the SQL Server service. When I stop the SQL Service on the primary server, it fails over to the secondary server as expected. I then start the service on the (now) secondary server and it comes back online as the secondary server. I then try to test that the service will fail back over when I stop the service on the new primary server.
However, when I stop the service, the secondary server now shows "resolving" and never comes back online. When I bring the service back up on the primary server, the secondary now shows as secondary instead of resolving. So to see if it's something about failing over from one server to another, I do a manual failover making the original primary server the primary again and everything is as it was originally.
I then stop the service on the primary server, but the secondary server now says resolving and the AG will not become available again until I start the service on the primary server.
It seems that when I first configured the quorum it worked fine the first failover scenario, then stopped working. I then added the file sharing witness, and failover worked the first time again, but not after that. For some reason after the initial failover it won't automatically failover again after that.
Config:
Servers: Windows Server 2012 Standard
SQL : SQL Server 2012 Enterprise SP1
it is possible to create Linked server with Failover partner option. I can query when primary server and getting the error when I set the DB Fail over. I have tried with following script and also gone through different sources, but failed. Please see the script and error below.
EXEC master.dbo.sp_addlinkedserver
@server = N'MIRRORLink',
@srvproduct=N'',
@provider=N'SQLOLEDB',
@provstr=N'Server=primary;FailoverPartner=mirror;network=dbmssocn;',
[code].....
In QA we have a two-node cluster with four instances of sql. In trying to add a fifth, I was given an IP address already in use so the install hung.
I removed it from the cluster but it is still there in the registry etc on the node I was working on.
I read about using the maintenance tab of the sql server install to "remove a node" but the terminology is confusing. To me a node is a physical server and an instance is an instance of sql server -- not the same at all but they are often referred to as the same thing.
I definitely don't want to remove one of the servers from the cluster.
y'day we faced situation one of the primary server went down and unable to failover the services to second node . by checking in logs we found
Cluster network 'Public' is partitioned. Some attached failover cluster nodes cannot communicate with each other over the network. The failover cluster was not able to determine the location of the failure. Run the Validate a Configuration wizard to check your network configuration. If the condition persists, check for hardware or software errors related to the network adapter. Also check for failures in any other network components to which the node is connected such as hubs, switches, or bridges.
In my environment always on is there. Today I observed that primary server fail over to secondary server .now the secondary server acting as primary role.
Can I know when is fail over is happened and who did the fail over. Is there any script to find this?
I am trying to install SQL Server 2012 onto an already configured and validated windows failover cluster (server 2012) but the process is hanging after installing the setup files.
The last entry in the log is:
running discovery on remote machine
and I've left it hanging like this for 4 hours and nothing happens.
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.
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
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.
I´ve been reading that SQL Server 2012 Always On is dependent on having a Windows Failover Cluster setup. Is that correct ?
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