Introduction

Dbvisit Standby’s new Network Layer is one of the exciting new features introduced in Dbvisit Standby version 7. Dbvnet’s functionality removes the dependency earlier Dbvisit Standby versions had on SSH for providing network communication between the primary and standby nodes. By making use of Dbvnet no additional SSH software is required to be installed, configured or maintained on Windows. When using UNIX based systems, Dbvisit Standby can now be configured to make use of the new Dbvnet (default option) or if required, SSH is still fully supported by Dbvisit Standby and can be configured and used on Unix based systems only. Password-less SSH authentication must be enabled between the primary and standby nodes if using Dbvisit Standby with SSH as communication layer.

On Linux (UNIX) based systems, SSH can still be used for communication and file transfer between the primary and standby server.

If your network has regular disconnects or is unstable - using SSH is recommended.

To revert back to using SSH, ensure that SSH_PORT=22 is specified (SSH user equivalence between the primary and standby must be enabled - passwordless authentication using keys)

To disable DBVNET and Enable SSH, the DBVNET_PORT is set to an empty (NULL) value in the DDC file: DBVNET_PORT=

Important: This option of using SSH is not available for Windows based systems. Windows based systems must use Dbvnet.

Using Dbvnet

Dbvnet is started as a background process and is run independent from the already known GUI (Dbvserver) background processes.
Dbvnet provides the following key features:

Dbvnet is located in the DBVISIT_BASE directory under the dbvnet sub-directory. Example Dbvisit Standby directory structure below:

dbvisit               <-- DBVISIT_BASE
 |-- dbvnet           <-- Dbvnet Home/Sub directory
 | |-- conf           <-- Dbvnet Configuration Directory
 | | `-- init.d
 | |-- doc
 | |-- log            <-- Dbvnet Log Files
 | `-- tmp
 |-- dbvserver        <-- Dbvserver (GUI) Home/Sub directory
 | |-- conf           
 | | `-- init.d
 | |-- doc
 | |-- log
 | `-- tmp
 `-- standby
   |-- conf       <------ New location of Dbvisit Standby Configuration (DDC) file
   |-- doc
   |-- log
   |-- pid
   |-- tmp
   `-- trace      <------ Default location for Dbvisit Standby Trace files

Stop and Start Dbvnet

Dbvnet can be stopped and started using the dbvnetd executable located in the dbvnet sub directory (example - /usr/dbvisit/dbvnet) when using Linux (Unix) based systems and when using Windows based systems using the Windows Services to stop and start the "Dbvnet" service.

Linux (UNIX)

Below is an example of stopping and starting the Dbvnet background processes on Linux (Unix).

oracle@dbvlin101[/usr/dbvisit/dbvnet]: ./dbvnetd stop
oracle@dbvlin101[/usr/dbvisit/dbvnet]: ps -ef|grep dbvnet
oracle   12641 12446  0 09:20 pts/1    00:00:00 grep dbvnet
oracle@dbvlin101[/usr/dbvisit/dbvnet]: ./dbvnetd start
oracle@dbvlin101[/usr/dbvisit/dbvnet]: ps -ef|grep dbvnet
oracle   12643     1  0 09:20 pts/1    00:00:00 ./dbvnetd start
oracle   12644 12643  0 09:20 pts/1    00:00:00 ./dbvnetd start
oracle   12645 12643  0 09:20 pts/1    00:00:00 ./dbvnetd start
oracle   12646 12643  0 09:20 pts/1    00:00:00 ./dbvnetd start
oracle   12647 12643  0 09:20 pts/1    00:00:00 ./dbvnetd start
oracle   12649 12446  0 09:20 pts/1    00:00:00 grep dbvnet

Once the Dbvnet background processes are started, you will notice 5 processes running.

Windows

Starting and stopping Dbvnet on Windows based systems is done via the Windows Services.

Below is an example showing the Windows service details for the Dbvnet Service. From here you can stop/start dbvnet.

It is recommended that this process be left with "Startup Type" as "Automatic"

Testing Dbvnet Communication

Once you have Dbvisit Standby installed on all the servers, it is important to make sure that the communication between the Primary and Standby servers are working. This can be done by making use of the Dbvnet Test utility provided with the Dbvisit Standby installation - dbvnet-test, which is located under the dbvnet sub directory. When using the default path this utility will be in /usr/dbvisit/dbvnet/dbvnet-test

To test communication between the primary and standby servers you can run the following recommended test commands:

To perform a basic status check which confirms that the primary and standby server can communicate using Dbvnet:
- dbvnet-test [-s|--status] SERVER[:PORT]
To perform a more detail check, testing network connectivity, you can run the following:
- dbvnet-test [-f|--fulltest] TMPDIR SERVER:PORT

In the example below, dbvlin101 is the primary server and dbvlin102 is the standby server. Dbvisit Standby was installed using default values and no additional configuration has been performed at this stage. Dbvnet and Dbvserver is running on both nodes, but only Dbvnet is required and used for these tests:

Test 1: Basic Status Check

oracle@dbvlin101[/usr/dbvisit/dbvnet]: ./dbvnet-test -s dbvlin102:7890

>>> Determining Dbvnet status on server dbvlin102:7890...


    Dbvnet on server dbvlin102:7890 is running.

From the above test you can see that Dbvnet was able to successfully establish a connection between server dbvlin101 and dbvlin102.

Test 2: Full Test - 10MB file is copied (and verified) between primary and standby

Note: When using the dbvnet-test -f option, please specify the temp directory that exists on both systems. This is where the temp 10MB file will be copied to test connectivity. Example usage: ./dbvnet-test -f TEMPDIR SERVERNAME:7890

This temp directory is required from Dbvisit Standby version 7.0.10.

Example:

oracle@dbvlin101[/usr/dbvisit/dbvnet]: ./dbvnet-test -f /tmp dbvlin102:7890

>>> Determining Dbvnet status on server dbvlin102:7890...
    Dbvnet on server dbvlin102:7890 is running.

>>> Running file transfer round trip on server dbvlin102:7890...
    Creating file '/tmp/dbvnet-test.tmp' containing 10 MB of data... - done.

  > Transferring 'dbvnet-test.tmp' to server dbvlin102:7890
    Progress: 0%...20%...40%...60%...80%...100% [11046 KB/s] - done.

  > Retrieving file "dbvnet-test.tmp" from server dbvlin102:7890
    Progress: 0%...20%...40%...60%...80%...100% [11209 KB/s] - done.
    Comparing checksums: all three checksums (local/remote/local) are
    identical. File transfer round trip finished successfully.

From the above test you can see that Dbvnet was able to successfully copy a temporary 10MB file between the two servers.

Note that the speed (transfer rate) is informational only and not an exact indication of the network speed.

You should run the above tests from both the primary and standby servers to ensure communication between primary and standby servers can be established after a new installation before you start the Create Standby Database process.

Once this is done you can continue to the next step which is the creation of a Dbvisit Standby Database Configuration (DDC) file.

Dbvnet Configuration Options

Dbvnet does not have a large number of configuration options and should work without any configuration changes in most environments.

Do not adjust any of the settings in the dbvnet.conf file located in DBVISIT_BASE/dbvnet/conf directory, unless instructed by Dbvisit Support.

The only parameter that can be adjusted manually in this file is the PORT you would like Dbvnet to use. By default the port number is 7890.

To adjust this port, stop dbvnet and adjust the parameter "bind_port = 7890" in the dbvnet.conf file followed by a restart of dbvnet. Note that if you do change this port number that you will need to adjust this on both the Primary and Standby servers and that Dbvnet must be restarted.

Dbvisit Standby Networking (Dbvnet and SSH)