We have two nodes availability group. The two nodes being SQL cluster1- node1 and SQL cluster 2- node2 and a Availability group listener. The Java application is connecting to this listener and all is working fine initially i.e application is able to perform both read/writes on the database, untill we do a failover.
The connector string is driverURL=jdbc:jtds:sqlserver://[Listerner DNS Name]:[Port]/[Database]
Say initially the node1 was primary and node2 was the secondary.
After failover, node1 becomes secondary and node2 becomes primary. Now the application is still able to connect to the database but only able to perform reads on the database. The application throws exceptions (which is mentioned in the title) if we try to do inserts on that DB.
Basically what I need is for the application to be able to perform read/writes all the time irrespective of which node is the primary. Any ideas ?
There should be no reason why you get a read-only database when the connection string is pointing to the listener. That's the point of the avail grp listener - to direct flow to the read/write (primary) database. Ping the DNS name and check that it resolves to the listener (before and after an AG failover). Unfortunatelyy I don't use Java so can't help you any further. Cheers, Mark.
Related
Background:
I have a Always On Availability Group Setup with 4 Nodes(DB1,DB2,DB3,DB4). I am using File Share witness hosted on some other server. All the nodes on AG are set to failover automatically. And as readable secondary option set to 'yes'.
Issue:
For instance, lets consider DB1 as primary node on both AG and WSFC. Now,whenever I stop the MSSQL service on DB1, DB2 or the other 2 becomes primary on AG. However, DB1 stays as primary host on the WSFC. The main problem here is whenever my application tries to connect to the DB, I get an error as "Failed to update 'Dbname' database is read only". But when I manually change the node of WSFC to the now Primary AG DB my application starts working. Can someone please help me out here.
whenever my application tries to connect to the DB, I get an error as "Failed to update 'Dbname' database is read only"
Your app needs to connect to the AG through the AG Listener, which will only be active on the node hosting the primary database replica.
If your app is connecting to the listener you need to troubleshoot the connection. Verify that DNS resolution is returning all the IP addresses, and that only the IP address hosting the primary replica has the requested SQL Server port open.
Trying with VoltDB cluster, created a cluster of 2 nodes with k=1
Cluster initialization was successful, both the nodes are up.
Now, how do i connect to this cluster, i could not find any documentation to setup single IP for cluster.
Will the client connect to particular node IP or cluster IP ?
I am using VoltDB community edition.
In general, you can connect to one node, or to multiple nodes. For simple usage, one node is fine. For a client application where you want lower latency and higher throughput, you should connect to all of the nodes in the cluster. See Connecting to the VoltDB Database for the java client, and in particular section 6.1.2 on using the auto-connecting client which enables you to connect to only one node and the client will automatically connect to all of the other nodes.
For command-line access, see the sqlcmd reference:
--servers=server-id[,...]
Specifies the network address of one or more nodes in the database cluster. By default, sqlcmd attempts to connect to a database on localhost.
Disclosure: I work at VoltDB.
If you wish to connect to a single node try
jdbc:voltdb://192.168.1.5:<port>
as the connection URL or if you wish to connect to cluster try
jdbc:voltdb://192.168.1.5:<port>,192.168.1.6:<port>,<any additional nodes you might have in your cluster>
as the connection url.
I am working on a project that requires a reconfigurement of the current Failover Cluster settings. The project itself requires the availability of a report server as well as the login by use of a windows authenticated account.
The current situation is: Server runs perfect while on the first node, but whenever a failover occurs, and the cluster switches over to the second node, there is an issue with gaining access to the report server. When the cluster is running on the second node, on SSMS the availability group shows that the cluster is in (Secondary) position, while the replicas themselves are as follows: Node1 (secondary), role: Secondary; node2: [blank], role: Unknown.
This also brings up an error saying having issues logging into to the report server from node2.
If anyone knows of anyway, or settings to be changed, I would be greatly appreciative.
Thank you!
I'm working on logs. I want to reproduce a log in which the application fails to connect to the server.
Currently the commands I'm using are
db2 force applications all
This closes all the connections and then one by one I deactivate each database using
db2 deactivate db "database_name"
What happens is that it temporary blocks the connections and after a minute my application is able to create the connection again, due to which I am not able to regenerate the log. Any Ideas how can I do this?
What you are looking for is QUIESCE.
By default users can connect to a database. It becomes active and internal in-memory data structures are initialized. When the last connection closes, the database becomes inactive. Activating a database puts and leaves them initialized and "ready to use".
Quiescing the database puts them into an administrative state. Regular users cannot connect. You can quiesce a single database or the entire instance. See the docs for some options to manage access to quiesced instances. The following forces all users off the current database and keeps them away:
db2 quiesce db immediate
If you want to produce a connection error for an app, there are other options. Have you ever tried to connect to a non-estisting port, Db2 not listening on it? Or revoke connect privilege for that user trying to connect.
There are several testing strategies that can be used, they involve disrupting the network connection between client and server:
Alter the IP routing table on the client to route the DB2 server address to a non-existent subnet
Use the connection via a proxy software that can be turned off, there is a special proxy ToxiProxy, which was designed for the purpose of testing network disruptions
Pull the Ethernet cable from the client machine, observe then plug it back in (I've done this)
This has the advantage of not disabling the DB2 server for other testing in progress.
Adding node fails Windows Server 2012 Failover Cluster for AlwaysOn Availability Groups in all AZURE, is leaving an apparent phantom VM node. How can I cleanup up?
Server property for target server VM is flagged as "clustered", but is not. There was another node added successfully, but when trying again to add the node , that failed earlier, does not work, as cluster manager reports back that target "xxxxx server is already clustered".
I evicted the the single node, then "destroyed cluster". Then created anewly named cluster. Added one node, but when trying to add the "problem" sql server VM, I get same return msg : "server is already in a cluster". When I remote into the target sql Azure VM, server manager shows the server as "Clustered". I can not find any way to clean this failed operation up.
When I open FO cluster mgr on the SQL VM, I see red-x'ed the cluster name of the cluster I had previously "destroyed". Same VNET, same subnet. Validates OK on cluster build up to point of failure when trying a add 2nd SQL VM node to cluster.
No solution was found after rambling thru msdn, technet. Had to delete azure vm,s completely, but note that in the
same cloud viewed thru ms new portal, parts still are displayed in those pages. Like Loose random balloons drifting around azure chaos...