This is my second post about the features of email archiving software. Yesterday, I discussed the features that are related to the archiving process. Today I will focus on the different ways emails are stored by archiving tools.

As files or in a database

There are email archiving solutions that only store the metadata in a database. The email bodies and the attachments are saved as files. It is also possible for only the attachments to be stored separately. Perhaps this method is safer when it comes to long-term archiving because one is not dependent on the database software. Who knows if its vendor will still exist in 20 years? However, search performance might be better if everything is stored in a database.

Whole object or individual parts

This topic is related to the one above. Emails can be archived in one piece or each part of an email (header/body/attachment) can be stored separately. Obviously, you have more search options if the email archiving solution is able to distinguish between the different parts of an email.

Format conversions

When it comes to long-term archiving, one of the key factors is the format that is used to store emails. Attachments in fancy formats might not be readable in the future because the corresponding viewers are no longer available. Thus, it can be useful if the email archiving solution supports conversion into common formats such as plain text, HTML, PDF, PDF/A or TIFF.

Copy or move

One way to keep your email server’s database lean without removing emails completely from the user’s mailbox is to archive only attachments and/or the email bodies. The header stays in the mailbox and the attachments are replaced with links, which allows the end user to access the complete email if required.

Encryption

Emails can contain confidential data. The fact that all of your organization’s emails are stored in one place is risky because it simplifies data theft. A frustrated employee can copy it easily to a portable hard drive and sell it to one of your company’s competitors. An encrypted email archive guarantees that only authorized people can have access to your organization’s communication data.

Compression

Email archives can require a considerable amount of storage capacity. Compressing emails and their attachments is one way of reducing the size of an archive. The compression rate is usually quite good for emails because they consist mostly of text.

Single-instancing

Another way to save storage capacity is to store multiple copies of an email or an attachment only once in the archive and replace the original objects with links.

Storage hierarchy

Enterprise archiving solutions are often able to store emails on a cascading hierarchy of storage media. New emails are stored on hard disks. After a configurable time period the emails are moved to tapes because they are cheaper than hard disks. Eventually, for long term preservation, they are moved to a WORM storage system.

Retention

Emails are usually archived for business-related reasons, not to preserve them for future generations. Hence, there will come a time when you want to finally erase them. Retention policies allow you to configure different retention rules depending on the type of the emails. For instance, retention time periods can be dependent on the recipient, the category or the size of an email.