---
title: "How to set a unique hash_salt for an individual site"
date: "2024-01-12T03:48:51+00:00"
summary:
image:
type: "article"
url: "/acquia-cloud-platform/help/92066-how-set-unique-hashsalt-individual-site"
id: "638377ae-3dd6-46b1-b6c9-4f6ad0e5c7fd"
---

Table of contents will be added

**Environment**
---------------

*   Multi-site
*   Acquia Cloud Site Factory

**Objective**
-------------

In certain scenarios, if your application is using a multisite setup (like Acquia Site Factory), non-specific "_PluginNotFound_" or "_Module not found_" errors can show up in the logs.

*       Drupal\Component\Plugin\Exception\PluginNotFoundException: "The {...} plugin does not exist. Valid plugin IDs...
    
*       Drupal\Core\Extension\Exception\UnknownExtensionException: The module {...} does not exist. in {...}/core/lib/Drupal/Core/Extension/ExtensionList.php {...}
    

This happens because Drupal keeps track of available resources (modules, plugins, etc.) in shared cache backends (like memcache or APCu) that use the _hash\_salt_ value to identify the multisite instance. If this _hash\_salt_ isn't unique for each site, it can cause one multisite's settings to "bleed" into the other site(s).

**Resolution**
--------------

1.  Confirm which sites are not using a unique hash: [How to find out if your Application is using unique hash salts between sites](/node/92341)
2.  Update settings for unique hash\_salts
    *   **Acquia Cloud Multi-Site**
        *   **​​​​​​​**Add this line to the end of all your sites' **settings.php** file:
            
                $settings['hash_salt'] = hash('sha256', $app_root . '/' . $site_path);
            
    *   **Site Factory** 
        *   **​​​​​​​**Add a variation of the below code to your post-settings-php hooks: [https://docs.acquia.com/site-factory/extend/hooks/settings-php/](/node/57275)
            
                $settings['hash_salt'] = hash('sha256', $site_settings['site'] . $site_settings['env'] . $site_settings['conf']['acsf_db_name']);​​​​​​​