The 3 Critical Aspects of Email Disaster Recovery

by | Dec 5, 2016

Everything You Need to Know about Email Disaster Recovery

Email is important to any business, and it’s never more important than when things go badly wrong. Customers and partners want to know what the situation is and how soon things will be back to normal.

A disaster recovery plan needs to set priorities for restoring service. Email needs to be near the top of the list, so that communication isn’t disrupted any longer than necessary.

Email disaster recovery has three aspects, from the most urgent to the least:

  1. Restoration of the ability to send and receive mail.
  2. Recovery of recent mail.
  3. Preservation of archived mail.

For businesses that use hosted email for everything, recovery isn’t a major issue. The mail provider will keep running even if the affected office’s computers are damaged. If the business maintains its own mail server, or if it receives mail through a host but stores it locally, then email needs to be part of the disaster plan. IMAP and Exchange servers store incoming messages. A POP3 server lets recipients download their mail and may or may not delete it, depending on how it’s configured.

Restoring communication

An email server on a company’s premises or in a data center can fail. It doesn’t take a full-blown catastrophe; hardware can go bad for no obvious reason. Even if it just takes a few hours to fix, losing communication isn’t good for business. If it’s part of a general failure, restoring communication is all the more urgent.

When a POP3, IMAP, or Exchange server, which handles incoming messages, goes offline, mail transfer agents will retry several times before giving up on delivery. If they can’t deliver a message for several hours, they  may send a notice back to the sender. Usually they won’t declare the message undeliverable for a couple of days. It’s not likely that any messages will get lost if service is back up within 24 hours, but the “bounce” notices will affect people’s confidence. If the server comes back quickly enough, senders will never notice there was a problem.

Setting up a cloud-based failover server allows the fastest recovery. The regular and failover servers both stand behind a routing switch, and if the regular server stops responding, the switch activates the failover server for as long as necessary. Mail continues coming in with almost no interruption.

Recovering current mail

Making failover work smoothly requires frequent backup. The failover server needs to pick up the job with little or no loss of data. Messages that the primary server receives but doesn’t back up could be lost till it’s restored, or permanently.

With a POP3 server, users’ own machines will have any messages that arrived before the last time they checked, but any mail that came in since then will still be on the server. If it was backed up, the failover server will send it to them the next time they check.

With IMAP and Exchange servers, all mail which hasn’t been deleted will be on the server, and it will be available from the failover server if it was backed up. Users may also have their own copies of some or all of their mail.

Retaining mail archives

Avoiding the loss of older mail can be a more difficult problem. Servers have a limited capacity, and eventually messages have to be deleted or archived. Most businesses aren’t systematic about retaining old mail, and it may be each user’s individual responsibility.

If retaining old messages is a legal requirement, or if business policies call for it, mail needs to be stored for some period of time. On the other hand, some messages may contain confidential information, so it can be a bad idea or even a policy violation to keep them around. Conflicting requirements lead to inconsistent user actions, and perhaps secret archives.

A business that needs to archive email needs an archiving policy that meshes with its disaster recovery policy. Everything that needs to be retained needs to be backed up.

To sum up: Keeping email communication working is a high priority in case of disaster. It requires special considerations beyond the normal ones of data retention and restoration. Keeping communication active through a crisis keeps up the confidence of customers, remote employees, and business partners.

Invenio IT will provide you with the services you need to get your systems running again quickly when disaster strikes. Please contact us to learn how.

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Dale Shulmistra is a Business Continuity Specialist at Invenio IT, responsible for shaping the company’s technology initiatives -- selecting, designing, implementing & supporting business continuity solutions to bolster client operational efficiencies and eliminate downtime.

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