Platform Considerations

This page is used to keep track of common platform considerations, mostly derived from Pantheon's distributed nature. Check back often, as we are keeping it up to date as we make improvements to address these limitations.

Browser Support for Pantheon's Dashboard

In order to focus internal development and engineering work, the Pantheon Dashboard supports the following browsers:

	Chrome	Firefox	Opera	Edge	Safari	Internet Explorer
Versions Supported	Evergreen Browsers - Last 4				Current + Last Year	Internet Explorer 11

Multisite

Pantheon supports designated use cases for WordPress Site Networks created by WordPress' Multisite feature.

We do not support Drupal Multisite. See blog posts: Why Drupal Multisite is not Enterprise Grade and Much Ado About Drupal Multisite.

One Application per Site

Each site supports a single Drupal or WordPress application. Placing a WordPress application to behave as the blog for a Drupal site, for example, is unsupported.

Highly Populated Directories

If you have individual directories with tens of thousands of files (e.g. an image repository) it may be necessary to refactor this file structure to see good performance on Pantheon. The danger zone begins at around 50,000 files in a single directory, and performance drops off suddenly at over 100,000 files.

Drupal itself is capable of managing uploaded content into different directories based on the date or user, which is preferable to dumping all uploads into a single place. Refactoring an existing large-scale site with this issue is usually simply a matter of re-arranging the files and then updating the files table in Drupal.

Email and Deliverability

Because of the cloud-based nature of Pantheon's infrastructure, we cannot ensure high-deliverability email originating from your Application Containers, as they have no fixed location. While all sites have access to a local Postfix service for testing and development, we recommend using an external SMTP gateway (SendGrid, for example) in production to ensure that your email is delivered.

See the email documentation for more details and suggestions.

Streaming Media

Because Pantheon does not provide transcoding, bandwidth-adaptive media delivery, or support for large files (see below), streaming media is not possible directly from the platform.

However, you can run a great streaming media website. To do so, Pantheon recommendeds that you find a service to handle the transcoding and streaming, whether that's YouTube, Brightcove, Vimeo, Soundcloud, or another provider. These services provide all the necessary components for great streaming media.

It is also possible to deliver smaller media files from Pantheon using progressive download, but the media will not automatically adapt to the bandwidth and capabilities of the device browsing the site, nor does Pantheon support "seeking" to arbitrary playback positions based on time. The actual media formats (encodings, containers, file name extensions) are unrestricted.

Large Files

Pantheon's file serving infrastructure is not optimized to store and deliver very large files. The bigger the file, the slower the transfer. Files over 50MB will experience a noticeable performance degradation due to our caching infrastructure configuration.

Pantheon cannot be used to host files over 256MB, no matter how the file is uploaded.

If you are distributing large binaries or hosting big media files, we recommend using a CDN like Amazon S3 as a cost-effective file serving solution. Modules such as Amazon S3 CORS Upload allow uploads directly to S3 from your Drupal site without using Pantheon as an intermediary.

Large Code Repository

When a code repo is larger than 2GB, it increases the possibility of Git errors when committing code on Pantheon. We suggest keeping multimedia assets out of the repo by moving them to a media file storage service such as Amazon S3, and using version control to track URLs.

Rename/Move Files or Directories

Files

Like file directories, files on Pantheon cannot be renamed or moved. Our SFTP mode doesn’t support the mv command, which is what most apps use when renaming or moving files. The workaround is to delete the old file and upload the new file.

Directories

File directories on Pantheon's file serving infrastructure cannot be moved or renamed. The workaround is to create a new directory, move all the files from inside the old directory into the new one, and delete the old directory.

IP-Address Based Security Schemes

IP-based security is not recommended on Pantheon - or any cloud platform because the actual IP address where code executes from can change as application containers are migrated throughout the infrastructure.

For more information, see Dynamic Outgoing IP Addresses.

Maintenance Mode

Pantheon may send a generic Maintenance Mode message during platform problems; this message cannot be customized.

Built-in Maintenance Mode for both Drupal and WordPress sites can be customized; clear caches when toggling.

Server Side Includes (SSI)

Pantheon does not and will not support Server Side Includes. We recommend converting those to use PHP includes.

PHP Short Tags

PHP short tags (<? ... ?>) are not supported on Pantheon. The PHP Manual recommends not utilizing short tags because they are not supported on every server. Additionally, using short tags can interfere with embedding PHP in XML. Avoiding their use leads to more portable, re-distributable code.

CORS

For sites that need to provide services with Cross-Origin Resource Sharing (CORS), adding the proper header should enable the resource. See  http://enable-cors.org/server_php.html

Sites that consume services using CORS, such as Amazon S3 CORS, do work on Pantheon.

Large (>100GB) File Backups

Large backups take longer, use more resources, and have a higher likelihood of failing.  Additionally, a 100GB tarball is in itself not particularly convenient for anyone.  For this reason, scheduled backups do not backup files for sites with footprints over 200GB (although code and database are backed-up as normal).  Despite the lack of backups, file content is highly durable and stored on multiple servers.

CSS Preprocessors

Pantheon does not currently support LESS or Sass/Compass CSS preprocessor languages. LESS and Sass will need to be pre-compiled to make traditional CSS stylesheets before being pushed to the platform.

.htaccess

Pantheon sites use NGINX to concurrently serve requests. The NGINX web server ignores distributed configuration files such as .htaccess for reduced resource consumption and increased efficiency. This configuration is standard across all Pantheon sites, and modifications to the nginx.conf file are not supported.

For details, see Using PHP as an htaccess Alternative.

nginx.conf

Pantheon does not currently support modifying the nginx.conf per site, as we run a highly tuned universal configuration file. All of the containers run a standard profile, and we have opted to keep this configuration to keep the nginx.conf lean.

Oracle Database Drivers

Pantheon does not currently support directly connecting to Oracle databases. Customers have successfully used the Pantheon Enterprise Gateway to connect to an external API on top of their Oracle databases.

PHP/Java Bridge

Pantheon does not currently support the PHP/Java Bridge.

General PHP Framework Support

Pantheon does not currently support any PHP frameworks outside of Drupal and WordPress. The platform is only optimized for Drupal or WordPress and no others. Although PHP will run, we can not assist you in getting the non-approved frameworks running in any way.

Unsupported Drupal Modules and WordPress Plugins

See Modules and Plugins with Known Issues for an up-to-date list of modules and plugins that do not work with or are not supported by Pantheon.

Inactive Site Freezing

Sandbox sites that are over a year old that have not had code commits or other Git activity for 6 months are "frozen". All requests to a frozen site will return a 530 Site Frozen error code, and the site's Dashboard will be unavailable.

You can reactivate a site with a single click. Simply visit the site's Dashboard and click Unfreeze site. Within a few minutes, the site will be ready for development again. If you experience any issues, a backup of the site is available and can be restored via the Site Dashboard.