Email Compression

Email  compression is the process of reducing email file sizes (as well as the sizes of any corresponding attachments). It often functions as an integral part of an email archival system.

When combined with deduplication, offline or cloud backups, and file stubbing, email compression allows email storage and archival costs to be kept to a minimum. Whether you’re running a small business email server or a vast enterprise mail network, storing the correspondence between employees necessitates compression to avoid unnecessary storage costs and comply with e-discovery standards.

Email Compression techniques

Techniques for email compression include:

• Single instance storage: A means of maximizing storage efficiency by eliminating duplicate copies of message bodies and attachments. Multiple inbox archives then share a single copy of the email or attachment, avoiding redundancy.
• HTML removal: Many email programs use HTML to encode and format the written message. The HTML formatting can dramatically increase file sizes over a plain text message, and the formatting means that the message itself is repeated, introducing redundancy and larger message sizes. This technique involves storing emails as plain text instead of using their original HTML content.
• Attachment aliasing: Large office and image file attachments are often the reason for high growth rates of email storage. if attachments are sent to groups of many receivers, bandwidth bottlenecks can significantly reduce the speed of the company's email infrastructure. Automation can remove large attachments, and archive them separately from the emails. This reduces inbox size for individual users, and allows databases indexes to exclude significant amounts of data. This speeds up query time, increasing productivity. It can also minimize storage usage if several users have received the same attachments.
• Lossless data compression: Email can also be compressed using standard compression techniques. For example, an inbox archive could be stored in .zip or related format. As another example, Microsoft Exchange used .pst files – a proprietary format – to compress and archive individual users’ inboxes.

Compressing email content provides a cost-effective alternative to additional investments in transactional storage. By reducing email storage overhead, companies can increase productivity, reduce labor spend on maintaining email servers, and also effectively comply with legal requirements for retaining email correspondence.