I know now that AlwaysOn feature HAS to be installed/configured on a Windows Clustering environment, BUT the secondary replicas, like the Disaster recovery replica residing in a different Data Center HAS to be also in a Windows Clustering environment or can it reside on a SINGLE SQL Server INSTANCE?.
View 6 RepliesWhile configuring SQL Server 2012 Cluster with Always on, why do we need two secondary replicas.
The attached link will describe the actual query. [URL] ....
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?
We had a big issue today during maintenance work in our SQL environment.
So our environment:
- 2x SQL Server 2014 Enterprise on Windows Server 2012 R2 (SRV1 and SRV2)
-- Both Hyper-V VMs on different Hosts
-- Both configured to an Windows Failover Cluster and AlwaysOn Availability Group (AG1)
-- AG Listener: AG1_lis
-- No shared storage (each Hyper-V Host has its own local storage)
-- Asynchronous Mode
-- SRV1 is primary, SRV2 is secondary SQL node
What happened?
- Shutting down Windows on SRV2 due hardware maintenance
- Cluster goes offline, AG1 goes offline
-- Error message: "Stopped listening on virtual network name 'AG1_lis'."
-- Error message: "The availability group database "DatabaseXY" is changing roles from "PRIMARY" to "RESOLVING" because the mirroring session or availability group failed over due to role synchronization."
Results?
- AG1_lis wasn't available for our applications and they stopped working properly because database connection was lost!
I think, I HOPE, this is not the normale behaviour when one node is shutting down (especially the secondary node!)
In always on under availability group server name properties can see the option Readable Secondary. In that for secondary server the Readable Secondary Option is YES and for Primary it is Read-Intent. I believe Read-Intent allows only read only connections and YES allows all user connections.
View 0 Replies View RelatedIn always on under availability group server name properties can see the option Readable Secondary. In that for secondary server the Readable Secondary Option is YES and for Primary it is Read-Intent. I believe Read-Intent allows only read only connections and YES allows all user connections.
What exactly it means for the primary and secondary?
I have an AlwaysOn Availability group configured between 2 nodes (Synchronous)
Automatic failover was working fine until recently
I can failover between the nodes manually but automatic failover doesn't seem to be working. In my earlier test, I would shut down the SQL Service on the primary and within seconds, the secondary replica would take over. Recently I have performed the same test and the secondary replica enters the resolving state and the DB in unavailable.
I have tried everything here: [URL] ....
The only change I made was changing the availability mode from Synchronous to Asynchronous - Could that be the cause?
Looking for info on ole/requirement of primary and secondary replica under SQL Server 2012 AlwaysOn.
View 4 Replies View RelatedI have a SP that runs on the primary in 18 min and 45 min on the secondary( poorly written cursor,trying to fix it).Both machines are Exactly the same.I ran them in the middle of the night when no one was on the Sec. Node as we use it for reporting.
PLE: 7,000+
AVG Disk sec/write below .01
AVG Disk sec/read below .01
CPU below 5%
both machines set a max dop 4
Secondary replica database(setup in async mode) of AlwaysON went in "restricted mode" during weekly reindex operation.
So I have tried below steps
1) Executed following statement on the same secondary replica database where the issue exists
alter database <DBNAME> set multi_user with rollback immediate
but it failed with the error saying "The operation cannot be performed on database "dbname" because it is involved in a database mirroring session or an availability group. Some operations are not allowed on a database that is participating in a database mirroring session or in an availability group. ALTER DATABASE statement failed."
2) Primary database is multi_user but still tried following command on primary replia database(thinking it will replicate)
alter database <DBNAME> set multi_user
but no luck. The secondary alwaysON database shows (synchronizing) as the alwaysON is set in async mode but the command doesn't replicate across secondary
so we are left with the only option to re-setup alwaysON but I want to avoid it as database size is huge..
any other options or am I missing anything?
MCP,MCDBA(SQL 2000),MCTS(SQL 2005),MCITP(SQL 2005)
I was working on a job to send me info each morning about database file free space and was noticing some odd things when looking at the log file VLFs for one of my databases in an AlwaysOn availability group.When I run DBCC LOGINFO on the secondary replica for this database, I get what I expect and most VLFs have a status of 0 (indicating the VLFs are reusable or unused). When I run DBCC LOGINFO on the primary replica, all of the VLFs have a status of 2 (active or recoverable).
Since log backups on the secondary replica in AlwaysOn still truncate the log in the primary replica, I would expect that the VLFs in the primary replica would also be mostly in a reusable or unused state. My log file sizes are the same size on each server and my backups are completing successfully. what might be causing the VLFs on the primary replica to have a status of 2 in DBCC LOGINFO when taking log backups from the secondary replica?
I have a Windows 2008 R2 Always on Cluster with 3 nodes (two in the primary site and one in the DR site).
Primary Site:
-Primary Site Server1
-Primary Site Server2
DR Site 1 (to be decommed):
-DR Site Server1
Our company is planning on decommissioning the DR site. But before we do this, we want to add a 4th site to the cluster. Migrate the data...and then decommission the original DR Site.
Is it possible to have this configuration:
Primary Site:
-Primary Site Server1
-Primary Site Server2
DR Site 1 (to be decommed):
-DR Site Server1
DR Site 2 (NEW DR Site):
-DR Site Server1
IF this is possible, do I simply add the new DR site to the existing cluster (same steps as adding the first DR node to the cluster when the cluster was originally configured? or are there special steps?
How many nodes can you have in a cluster with SQL 2012 alwaysOn.
I understand that availability groups are limited to 5 nodes but if you had a 10 node cluster and decided to create multiple availability groups using various nodes within the 10 nodes but never exceeding 5, is that possible?
Or is there a counter or some validation from SQL AlwaysOn that actually hard limits to a grand total of 5 nodes in a cluster?
Can we make SQL 2012 Always ON over the normal SQL Cluster 2012.
View 3 Replies View RelatedWe have an existing SQL Server 2012 Enterprise cluster with 2 nodes (active-active) and uses Windows 2008 R2 OS. We are looking for a way to increase HA as well as offload backups to secondary server and it was suggested that AlwayOn could be an option.
The questions I have are:
1) Is it possible to turn on AalwaysOn feature on an existing cluster?
2) If yes to above, does the secondary replica need to exist as a node on the same cluster or can it be on a completely different cluster?
3) If the secondary replica is on the same cluster (i.e. we add a 3rd node to existing 2 node cluster), can that node be provisioned with storage from a completely different SAN? (i.e. Node 1 and Node 2 accesses LUNs on SAN1 and Node 3 accesses LUNs on SAN2).
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.
When I fail an availability group between subnets, I am finding that the DNS entry in DNS is staying. So what happens is the Availablity Group listener has 2 records in DNS, one for each IP. This causes the App to timeout at times, since DNS will return either of the two IP's.
View 9 Replies View RelatedHow can we change the backup replica in Always on Cluster. I am not able to take backup because of this.
View 7 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.
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 ?
I´ve been reading that SQL Server 2012 Always On is dependent on having a Windows Failover Cluster setup. Is that correct ?
View 6 Replies View Relatedi have created a new login in primary server and provided dbowner permission to primary db.how do i transfer this login to secondary server and assign the same permission to secondary db ?
View 2 Replies View RelatedI was able to do windows cluster successfully on vmware but after destroying it and I wanted to rebuild cluster on same nodes with same vmnode as DC.But Clustering kept failing.... and I had to rebuild entire vmnodes ,ISCSI SAN and Clustering from scratch...
How do I get over this problem.I want to manage cluster so it remains stable after failover or even after shut down of VMnodes????
We have set up SQL server 2012 alwaysOn availability group on windows 2012. It runs and fails over successfully. Recently, a VMWare creates a snapshort of a primary and it breaks a cluster. We saw errors in a cluster log.
In VMware setting, The quiesce option is turned off for these VMs. Also, we configured cluster setting :Windowssystem32> (get-cluster).SamesubnetThreshold = 10 ( Relaxed )
Cluster node 'Test1' was removed from the active failover cluster membership. The Cluster service on this node may have stopped. This could also be due to the node having lost communication with other active nodes in the failover cluster. 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 adapters on this node. Also check for failures in any other network components to which the node is connected such as hubs, switches, or
File share witness resource 'File Share Witness' failed to arbitrate for the file share 'TestTEstQuorum'. ensure that file share 'TestTestQuorum' exists and is accessible by the cluster.In alwaysOn error log, A connection timeout has occurred on a previously established connection to availability replica 'Test1' with id [CAD40D99-E333-457E-9993-BBE977D2CDA2]. Either a networking or a firewall issue exists or the availability replica has transitioned to the resolving role.
how to add the Secondary Data file to the Database that is a part of the Always on Availability on SQL Server 2012.
View 3 Replies View RelatedI noticed that after a SQL AlwaysOn failover, one of the DB in the secondary replica is stuck in Restoring state. The primary replica shows that it is in a synchronized state. These are the error logs from SSMS. How do I trace the cause of the problem?
Error: 5901, Severity: 16, State: 1.
Nonqualified transactions are being rolled back in database for an AlwaysOn Availability Groups state change. Estimated rollback completion: 0%. This is an informational message only. No user action is required
Error: 18400, Severity: 16, State: 1.
One or more recovery units belonging to database failed to generate a checkpoint. This is typically caused by lack of system resources such as disk or memory, or in some cases due to database corruption. Examine previous entries in the error log for more detailed information on this failure.
The background checkpoint thread has encountered an unrecoverable error. The checkpoint process is terminating so that the thread can clean up its resources. This is an informational message only. No user action is required.
I recently configured SQL Server 2012 AlwaysOn Availability group using two nodes - a primary and one secondary read only replica. The group is residing on a windows 2012 cluster with an smb file share as the quorum. I am able to successfully failover through SQL and through the windows 2012 cluster. When I look at the group dashboard on the primary server and view the Operational state of each node I notice an odd value. The secondary role server is listed as Unknown. I also noticed that the Availability replicas node icons in object explorer are displaying the same icon on the primary server but on the secondary server, the primary server is shown as a server with a question mark.
Am I missing a permissions setting or is this normal behavior.
For example:
ServerA is the primary
ServerB is the secondary
ServerA lists the servers in Object Explorer as:
ServerA (Primary)ServerB (Secondary)
ServerB lists the servers in Object Explorer as:
ServerA ServerB (Secondary)
The primary is never listed a primary on the secondary server. Again failovers are working properly, but I want to be sure I am not missing a setting somewhere.
Recently I have faced one DBA interview, below is the question they asked me.
" Does AlwaysON secondary replica support Full backup, if it is not why"?
I know AlwaysON secondary replicas support only copy_only and tlog backups, why they wont support full backup?
I have a two node HA Always on group using a Listener. I would like to force a certain AD group to always be forced to the secondry node as they would only ever need to run select statements. If there an easy way to do this without using logon triggers?
View 6 Replies View RelatedHello,
Does anyone here know how to properly add a secondary IP address (VIP) to a SQL 2005 failover cluster? I have looked for articles, but so far I can only find references to how to change the VIP on a cluster, not how to add additional VIPs.
I have added the VIP as a resource in the proper resource group, and added it as a dependency to the SQL Server resource, and although the active server properly registers the secondary VIP, the SQL Server process does not listen on that IP. Vexing.
Thanks.
If the primary master server become permanently unavailable, following a hardware failure for example, what could steps to promote the secondary master to the role of primary master.
The Secondary server is a updateable subscriber and there are other servers also in the cluster with read-only subscription.
As per my tests if primary goes down, we can create new publication on secondary and create its subscriptions.everything should work fine after that.
if primary comes up in any case that can create problem in new cluster so we should take care in this regard
please let me know if something is missing here.
can we join a node in a windows cluster which is already in a different cluster?
We have this requirement as we need to setup readable secondary ( always on AG) on the third node.
We are planning to change all IPs of PRODUCTION Failover Cluster Setup. In my cluster setup ... we have 2 Physical Nodes with windows-2008, Roles are MSDTC and SQL-2008R2.
IP change for:
1. Both Nodes(Physical)
2. MSDTC
3. SQL Server
4. windows Cluster
So Almost... All IPs are going to change.
Im DBA here, I need to take care of SQL cluster and MSDTC. But I haven't performed this activity before.So I'm worrying about Impacts and consequences of this change. steps how should I perform this activity.