Amazon offers some of the most compelling services available on any platform, including the first and still largest generalized public cloud platform (EC2), probably the largest distributed key-value store on the planet (S3), and many other compelling products that are paid for on a month-to-month basis. What’s not to love?

On the other hand, Amazon products, while representing a great value for infrequently required assets, realize quickly compounding transactional costs. Let’s examine the costs of running a normal email service on Amazon, for instance.

(Note: it’s not really possible to run a mail service on Amazon anyway because most mail servers will not accept email sent from Amazon EC2 dynamic IP’s, and Simple Email Service is really only designed to send email from certain named senders. A lot of mail sending services have popped up to provide email sending services for EC2 customers, but most of them suffer from two major issues: charging per sent basis rather than a flat, low monthly fee like regular virtual servers or Beckbox, and usually not even relaying incoming email, let alone individual mailboxes.)

Let’s leave out the costs of EC2 for the moment and just look at the costs of storing email in S3. Add on the costs of whatever EC2 server you want onto the total below.

I’m probably a good example of a moderately-heavy user. I receive about 150 emails per day. Total daily is probably around 5MB in terms of storage. A naive calculation would put S3 costs at 5/1000 * 30.5 days/mo * 12 cents/month = 2 cents per month growth, and the cost of storage for my 7GB or so of email at around 84 cents per month. Bandwidth costs would be approximately the same as pure storage costs, presuming that the user reads every single email in his inbox. 88 cents for a single, fairly heavy user — not bad, right?

Not so fast.

Let’s ignore the fact that every file write would also need index database writes, etc, even for a fast-and-loose mail data structure like Maildir.

We also have to calculate costs of writing and reading those emails:

Transactional cost of writing: 150/1,000 * 1 cent * 30.5 = $4.58 (PUT)
Transactional cost of reading: 150/10,000 * 1 cent * 30.5 = $.46 (GET)

Lists are much more difficult to calculate — let’s assume that the mail client checks for new mail every five minutes, eight hours a day, but using minimal bandwidth for that (enough to only focus on the transaction costs for this mail checking/LIST operation): 8 * 12 * 30.5 / 1000 = $2.93. That number will spike if your user checks more frequently or more than one listing or has more than 1,000 files in his inbox.

Wait, did you catch that? writing those files alone cost almost five times as much as the pure storage costs.

Total costs would be:

New storage (5MB):   $.02
Existing storage (7GB): $.84
Bandwidth (5MB): $.02
Writing transactional costs: $4.58
Reading transactional costs: $.46
Listing transactional costs: $2.93
Total: $8.85 per month (for one user)

We’re ignoring extra costs that are more difficult to quantify such as index storage and writes, complex list operations, listing more than 1000 records in a folder, searching, etc. Presumably, you’d architect in some caching layers in your front-end app servers, but you still need to check S3 (or add another layer of abstraction like a database) at least once every five minutes unless your users don’t mind delays of five minutes to get email.

Think about that. $8.85/mo for ONE moderately heavy user — the actual cost of serving email for one user. I guess you probably don’t want to build the next Gmail on Amazon, and I have customers who have a lot more email than me — people who just save everything. Don’t forget, ideally I’d either mark up Amazon’s cost because of the solution I created, charge the end user an administrative fee, or something, so the end user cost would be even higher. Probably not the best platform for email!

Let’s cut Amazon some slack. Most users aren’t power users. If you have 10 of those and 50 users who do half as much, you’re looking at $88 for the heavy users and $221 for the lighter users ($313).

Wait. Now we’re up to $313 for sixty users. A single Beckbox could easily handle all that for a fraction of that monthly cost, using simple, stable, reliable, well understood technology that have been around for years if not decades. If you need real-time reliability and an eight-hour outage every year or two due to hardware failure would be an issue, then adding database and filesystem replication can make sense, still at a fraction of Amazon’s costs.

The worst part of this whole picture: you’d have to write everything from scratch and work around the eventual consistency model of Amazon’s infrastructure. Eventual consistency is awesome, but can add some challenges. You’ll probably have to write a custom IMAP or POP3 server. Probably a custom SMTP server. Probably a custom webmail app. So this is what you have to ask yourself: is this your value add? Are you even in this business of building a mail solutions? (I am, and I still think Amazon costs too much for this sort of app.)

Alternatives: Microsoft Exchange. (very expensive, but Rackspace has a neat offering that’s worth checking out.) Or Gmail. (cheaper, but a lot of people find the privacy, lack of control, and difficulty of integrating other servers into Gmail to be extra challenges that aren’t worth the effort.) Actually, Exchange is pretty proprietary, too.

On the other hand, Amazon really does have a lot of great tools, highly scalable, if you can work around the latency (delays) and possible lack of immediate consistency. Extra architecture time and costs, but doable.

In my view, though, sticking with Beckbox (or another VPS provider, if you prefer) for email makes a lot of sense. I want to build a bunch of things myself at Amazon, but a careful analysis of existing alternatives helped me decide to found Beckbox. (Of course, you can use Beckbox for other things, like running your website, too. We don’t charge you extra for every little thing like cloud providers do.)

One more quick example: let’s say that for reasons of SEO you purchase 1,000 domains and want to host them. How much for DNS services at Route 53? $1,000 per month. Beckbox: free (run your own DNS, it’s easy.) (Granted, Route 53 is better, but $1,000/mo better? DNS requests are almost always less than 150 ms anyway.)