The VoltDB Enterprise Manager lets you define, administer, and monitor VoltDB databases from a single easy-to-use web interface. You can manage multiple databases and multiple servers all from a single instance of the Enterprise Manager.
To do this, the Enterprise Manager presents you with a dashboard for viewing the activity within a database, modifying its settings, and starting and stopping either the database or individual servers. But before you get started, it is a good idea to understand how the dashboard operates. This chapter introduces you to the components of the dashboard and how to use them. The following chapters explain how to use the dashboard to perform specific activities.
The Enterprise Manager interface is made up of three main components:
The main component of the Enterprise Manager interface is the dashboard. The dashboard lets you examine the configuration and performance of one database at a time.
The left side of the dashboard summarizes the configuration of the database, including security settings, K-safety, snapshotting, and export. There are separate panels for database configuration, catalog selection, snapshots, and export management. Click on thebutton in each panel to modify the settings.
The configuration information also includes a list of the servers assigned to the database. Click on thebutton to add servers to the database. By clicking on the name of a server in the list you can choose to start or stop it (depending on the current state of the database and the server). You can also remove the server from the list or replace it with a different server.
The right side of the dashboard provides real-time information about the performance of the database, including summaries of latency, throughput (transactions per second), memory, and CPU usage, as well as detailed tables showing the volume of data per table and invocations per procedure. The right side of the dashboard also includes a log viewer for reviewing any log messages generated by the individual servers or the management tool itself.
Depending on what information you want to review, you can switch the data table between views of data volume or procedure invocations. You can also expand/collapse the display of the data tables or the log viewer — or both — by clicking on the heading above each section of the dashboard.
The list of databases on the left side of the dashboard lets you select which database to view in the dashboard. It also gives you a quick view of the status of all your databases.
To view a database in the dashboard, click on its name in the global list of databases and selectfrom the popup menu. There are additional actions you can take directly from the list, including starting and stopping the database, putting it in admin mode (pause), or removing it from the list (as long as it is not running).
Each database in the list displays an icon indicating its current state. You can use these icons to tell quickly whether there are any issues with your database infrastructure. Table 3.1, “Database Status Icons” explains the meaning of each icon.
Table 3.1. Database Status Icons
|Database is not running.|
|Database is running properly.|
|Database is running in admin mode (paused). The database is available for administrative access, but other clients cannot queue transactions until the database "resumes" and leaves admin mode.|
|Database is running, but not as configured. This means one or more servers are not running and the database is not at its originally specified K-safety value. This may be caused by an error or intentional action (for example, if the operator stops a server).|
|An unexpected error has occurred and the database is no longer running. Note that if you stop the database explicitly, the icon changes to gray (stopped). The red icon only occurs if the database stops unexpectedly due to errors of some kind.|
The section of the interface above the dashboard includes the VoltDB banner, the global server list, and the Help menu. The global server list icon and the help menu are to the far right of the banner.
The help menu brings up the About dialog box. The About box lists the currently installed version of the Enterprise Manager, information about the active license, and a link to the online documentation.
|Clicking on the Servers icon brings up a list of all of the servers known to the Enterprise Manager. When you define a database in the Enterprise Manager, you must assign servers to run the database before the database can be started. When you add servers to a database, those servers are automatically added to the global server list.|
When you remove a server from its assignment to a database in the dashboard, it does not remove the server from the Enterprise Manager. It stays so it can be assigned to another database later. If you want to remove the server definition entirely, open the global server list, click on the server name and selectfrom the popup menu. (The server must be removed from all databases before it can be deleted.)
Another use of the global servers list is to show you the databases to which a server is assigned and their current status. Click on a server name to see its properties and the status of the databases in which it participates.
 The Enterprise Manager manages databases that are defined and started using the web console or the REST interface only. It cannot correctly discover or manage databases started manually, and it cannot detect management actions performed manually through system procedures such as @UpdateLogging or @UpdateApplicationCatalog.
Mixing use of the Enterprise Manager and manual invocations of system procedures that modify the database is neither recommended nor supported. For each database (and its associated servers), use either the Enterprise Manager or manual processes for starting and managing the database.
Note that this restriction applies to procedures that modify the database schema or server configuration only. The use of read-only or non schema modifying system procedures does not impact the management of the database.