Prevent excessive IMAP activity

When it comes to checking your email accounts, the most common email protocol used these days is the IMAP (Internet Message Access Protocol) one. The way that IMAP functions, it can become intensive and excessive in its usage when on a shared server, causing upwards of 100% CPU usage and requiring a lot of disk activity on both the server and connecting IMAP device as IMAP folders and synced.

Typically you'll be alerted by our system administration team if there are any signs of your IMAP accounts causing problems leading to excessive server loads on the shared server. However there are some things you can do on your own to help prevent your accounts from every possibly being a problem in the first place.

POP3 vs IMAP

The POP3 (Post Office Protocol) is the older mail protocol and it will simply download all of your email off of the server and into your email client. This is great if you typically only need to check your email account from one computer, as all of the mail will only end up on that one machine

However a lot of the time you might check your email on your desktop, laptop, smartphone, tablet and more, and this is where the IMAP protocol is typically recommened. With IMAP your inbox lives on the server, and then any IMAP device connecting to your account will simply syncronize down all of your messages and IMAP folders on each connection.

Why not use IMAP all the time?

It might seem like you'd only want to ever use IMAP, but one draw back that does come along with using IMAP is that if you have a large volume of messages living on the server, each time your IMAP client connects to the server to check for new messages it has to sync everything in your Inbox folder down.

Typically we can see issues with the usage coming from IMAP accounts once the account has surpassed around 1,000 messages in their main Inbox folder. Now this isn't to say that you should only be keeping a total of 1,000 messages per email account, but you should understand what your IMAP client is having to do each time it connects to the server when you don't break up your messages into separate IMAP folders and just use your main Inbox for everything.

For instance let's say you have 10,000 messages on the server in your account all in the Inbox, you want to check to see if you've received any new messages today, so your IMAP client connects to the server, downloads the headers for all 10,000 messages, and then tells you there aren't any new messages. On the surface this can seem harmless, but typically you'll have your mail client set to sync new messages on an interval of about every 15 minutes or so. This excessive syncing of message headers again and again just to check for new mail can become overbearing on the shared server.

Instead, usually you'd only want messages from about the last 30 days or so to remain in your main Inbox folder, then once you've read something it should be archived away into a separate IMAP folder. As an example I have IMAP folders setup for "Bills", "Newsletters", and "Websites". So if I get an email from my cell phone company saying my bill is due, I move it into my "Bills" IMAP folder, and now everytime I check for new mail, my IMAP client doesn't have to re-sync that message because it's no longer in the main Inbox folder.

Available solutions for heavy IMAP activity

When it comes to preventing excessive IMAP activity in the first place, or resolving it after it's been identified as problematic, there are several options available to you to help. If you've received a notice about excessive IMAP activity coming from your account please response to that notice letting us know which options you'd like to employ.

If you decide to opt for either of the server archving options then we'd also recommend reading our guide on subscribing to email folders in an email client to learn how you'd view the newly created IMAP archive folders on the server.