Documentation forSQL Sentry

SQL Sentry Components and Architecture


SQL Sentry Components

Note:  Due to product name changes between versions and branding, you may have SentryOne, SQL Sentry, or a combination of these names in your installed SQL Sentry components.

SQL Sentry consists of the following components:

Component Purpose
SQL Sentry client Provides a thin client interface for viewing and managing collected information.

Associated application services and processes: 
  • SentryOne Client.exe
SQL Sentry monitoring service Collects event metadata and historical information for the monitored device(s).

Associated application services and processes:
  • SQLSentryServer / SentryOne.App.MonitoringService.exe
  • SQLSentryServer / SQLSentry.App.DiskSynchronizer (Note:  prior to version 2021.8, it was SentryOne.App.DiskSynchronizer.exe)
SQL Sentry database A SQL Server database that stores event metadata and historical information collected by the SQL Sentry monitoring service.

Note:  The default name for this database is SQLSentry. Other versions may have used SentryOne as the default. Some setups may use custom names, such as SQLSentry-US and SQLSentry-UK.
SQL Sentry controller When using EPI, this service controls the SQL Sentry services, allowing them to be managed remotely. It must exist on all machines where a monitoring service, portal service, or client is installed for the EPI version of SQL Sentry.

Associated application services and processes:
  • SentryOneController / SentryOne.App.ClientBootstrapper.exe
  • SentryOneController / SentryOne.App.ServiceBootstrapper.exe
SQL Sentry Portal If using the self-hosted version of SQL Sentry Portal, this service runs on the machine where the portal is installed.

Associated application services and processes:
  • SentryOneMonitorPortal / SentryOne.Monitor.WebClient.Web.exe
Miscellaneous processes & services (things that may need to be added to a safelist in your security software, if applicable)
  • SentryOne Report Viewer / SsrsViewer.exe
  • SQL Sentry Scheme Handler / SqlSentrySchemeHandler.exe
  • Startup Wizard / SqlSentry.StartupWizard.exe
  • Service Configuration Utility / SentryOne.App.MonitoringService.Configuration.exe


One SQL Sentry monitoring service is typically required for every 50 to 100 monitored targets. Install multiple monitoring services for scalability, redundancy, or to collect information from remote sites. Normally a SQL Sentry client is installed on each DBA's workstation.


  • See the Implementation Examples section of the Recommendations article for additional information on the number of SQL Sentry monitoring services.
  • All SQL Sentry monitoring services and clients connect to the same SQL Sentry database.


  • SQL Sentry doesn't attempt to replace SQL Server Agent, Windows Task Scheduler or any other scheduling agents. SQL Sentry communicates with these schedulers to determine event status and collect history and performance information using a lightweight polling architecture. 
  • SQL Sentry doesn't require installed agents on each monitored target which dramatically reduces associated setup and maintenance overhead of agent-based systems. SQL Sentry also doesn't install a database on every monitored SQL Server. See the Watched Target Objects article for details on which database objects are placed on a watched SQL Server target.
  • There are times when the SQL Sentry client connects directly to the watchedtargets (monitored servers). For more information about when that happens, and how it can be secured, see the Client Security article.

SQL Sentry Architecture Examples

Overall Example

SQL Sentry Architecture

Example with SQL Sentry Portal and EPI

When using the EPI version of SQL Sentry, the components remain the same, but there are controller services and bootstrappers associated with some components. For example, when the SQL Sentry client is installed via EPI, it includes the client bootstrapper which allows for updates to be pushed out automatically to the clients during the upgrade process.

SQL Sentry Installed Software Components and Architecture

Alerting and Response System

For its alerting and response system, SQL Sentry uses the concept of conditions and actions. Conditions describe the various states of monitored objects in your environment. Configure actions to take place when a condition is met.

All actions work on the principle of inheritance, meaning that an action configured in response to a condition being met at the global level (All Targets node in the Navigator pane), is automatically passed down to all applicable objects below it. This allows you to define global actions for the most common issues across your environment once, and have those passed down to every monitored target automatically.

Refine actions at each level as needed to determine what happens in response to events occurring in your server environment. Each instance type supports multiple conditions and actions. 

Configuring actions globally significantly reduces the setup and configuration time required to implement notifications. For example, by enabling the Send Email action for the global SQL Server Agent Job: Failure condition, you automatically receive email alerts for any SQL Agent job failures across your enterprise. The only requirement is that the SQL Server instance and its jobs are watched by SQL Sentry. For a more detailed explanation of how conditions and actions work, see the Alerting and Response System topic.

Watching Instances and Objects

Throughout this document you'll also see the term Watch used frequently, in the context of watching instances or objects. When you have SQL Sentry Watch an instance or object through the context menu this simply means that SQL Sentry begins monitoring it.

Consider the following rules regarding watched instances and objects:

  • When an instance is Watched, SQL Sentry monitors the instance and fires any applicable conditions for the instance based on its type.
  • When an object is Watched, SQL Sentry monitors the object and fires conditions for the object based on its type.
  • An instance can be Watched without watching any of its objects.
  • If any object on an instance is set to Watched, the instance is automatically set to Watched.
  • An object and its instance must be Watched to utilize SQL Sentry queuing, chaining, and performance monitoring features.