---
title: "About Multi-Tenancy"
slug: "about-multi-tenancy"
description: "Learn the basics of Multi-Tenancy and how a single server can support multiple independent Decisions instances."
updated: 2026-07-13T15:01:50Z
published: 2026-07-13T15:01:50Z
canonical: "documentation.decisions.com/about-multi-tenancy"
---

> ## Documentation Index
> Fetch the complete documentation index at: https://documentation.decisions.com/llms.txt
> Use this file to discover all available pages before exploring further.

# About Multi-Tenancy

## Overview

**Multi-Tenancy** is a **Server** **Architecture** that allows a single machine to run multiple independent installations of a software as individual **Instances** across other machines or VMs. The following document discusses some of the basics and functionality of Multi-Tenancy.

[Embedded content](https://www.youtube.com/embed/r3V9kZxLoKg)

Multi-Tenancy Architecture is Not Supported with the Deployment Tower in v10Within the Deployment Tower, the Multi-Tenant model is being replaced by **Organizations**. Each Multi-Tenant instance should be created as a separate organization, and the required environments should be associated with that organization. This approach provides the same benefits of tenant isolation and centralized account management, while aligning with new v10 architecture.  
  
**Note:** users upgrading to v10 without using the Deployment Tower can continue use of the Multi-Tenant architecture with full functionality.

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## Control Instance

The server responsible for hosting the application and its database is called the [**Control Instance** **Server**](https://documentation.decisions.com/version-10/docs/multi-tenancy-setting-up-a-control-instance). This is where [**Tenant**](/version-10/docs/about-multi-tenancy#tenant-instance) maintenance is handled and where relational data about the Tenant is stored. **System** **Administrators** can control **Permissions**, **Account** **Assignments**, and additional parameters from the Control Instance.

Warning About Developing on a Control Instance

It is NOT recommended to develop on a **Control** **Instance.** They are used for managing **Tenants**. Changes that negatively impact the Control Instance through testing may affect the Multi-Tenant Server it is built upon.

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## Tenant Instance

A [**Tenant**](https://documentation.decisions.com/version-10/docs/multi-tenancy-adding-and-setting-up-a-tenant-instance) is one of the independently running instances on a **Multi-Tenant Server** with the ability to customize parts of the application, such as the look and feel of the **Portal**. Each Tenant runs on its own database with its own secure install, so data is isolated and remains invisible to other Tenants.

Multi-Tenant Environments The diagram below illustrates the relationship between a **Control** **Instance** **Server** and its multiple **Tenants** in a **Multi-Tenant** environment. 

![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1782760664306.png)

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## Flexibility

**Multi-Tenant** setup is a simple process via the [DecisionsServerInstaller.exe](https://releases.decisions.com/Releases/) file. This achieved by selecting one of the respective options from the **Select** **Installation** **Type** screen; either **Multi-Tenancy Control** or **Tenant**. Users do not have to alter the **Settings.xml** file like in some older versions. ![](https://cdn.document360.io/6ef8bcc1-6489-4486-9ad1-83acff7e5df0/Images/Documentation/image-1782242728242.png)

Additionally, this method provides v9 Installations the ability to be able to create additional Instances from the user's desired location. Such abilities provide flexibility, such as creating a Multi-Tenancy consisting of multiple Instances on the same [Local File System/machine](https://documentation.decisions.com/version-10/docs/multi-tenancy-setting-up-multi-tenancy-with-provisioning) or across multiple systems or virtual machines.

Further, as desired, user Accounts can be assigned to multiple Instances by the [Control Instance](/version-10/docs/about-multi-tenancy#control-instance).

Self-hosting is not an available option when installing Multi-Tenancy.

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For more information regarding **Multi-Tenancy**, see [**Decisions Forum: Multi-Tenant**](https://support.decisions.com/forum/forum23-multitenant.aspx).