These days, people are finding new and ever more innovative ways to squeeze as much performance as possible out of their sites. Having a high performance VPS is a key aspect of that: if your pages load slowly, you’ll put off visitors, and crucially, search engine rankings may be impacted. It has been said that it takes as little as three seconds for someone to decide whether to proceed with their ‘journey’ on a website or not, and that isn’t a surprise: it’s a perfectly human thing to be impatient and demanding, and if you can place your order faster elsewhere, then why wait around?
We always recommend that clients with image intensive sites, or sites with large documents, video streaming and downloads, always use a CDN to reduce load times. Even on our own site, a website that is light on images, we use a CDN to boost performance – in this case, Amazon CloudFront. This blog post is about how and what you should choose if you’re considering a CDN.
So, what is a CDN?
CDN stands for Content Delivery Network, something that uses clever technology such as anycasting and geographic DNS routing to ensure that your content always gets served from the node that is closest to you. They distribute your files across a global network of POPs (points of presence) and serve your visitor from the nearest POP to them. It’s all about latency and reliability: the less between you and say, a static image file, usually, it’ll load faster, and there will be less chance of connectivity issues along the way. They’re optimised for compressing and serving content incredibly quickly, but as with web hosting, you can’t compare them easily. There are a multitude of factors you have to consider:
- Your visitors: where are they based, and does the CDN offer a POP near them?
- Origin pull or content push solutions: one will pull traffic from a directory on your site and distribute it when it is first loaded, caching it for a certain amount of time. The other will require an upload to a centralised storage space.
- Manual cache flushing & other technical features: if you want to modify a file, will you have to wait for users to see it?
- Cost per GB of transfer and for storage
- Support with setup
- Pricing model: do you have to buy large bandwidth blocks, or do you pay-as you go?
Up until recently, we used MaxCDN to serve images from our site. Factoring in the above, that wasn’t the best decision as it didn’t offer many POPs in Europe, and pricing, although cheap for blocks, was not pay-as-you-go. Our site uses highly compressed images, and has very few of them, thus making a $35/TB/yr solution completely unnecessary.
We now use Amazon CloudFront, which offers five European POPs, ten North American POPs, plus three in Asia. Overall, that’s a great mix, and seems to serve our customers incredibly well. On top of Amazon S3 storage costs (amounting to a few cents a month), we pay $0.15/GB – $0.20/GB depending on the CDN region that serves our content. For a few gigs a month, that’s a really nice deal, and the coverage is significantly better than that of MAX. However, had we been serving video intensive content, we may have been inclined to consider them.
The one key downside to Amazon CloudFront (the name of the Amazon CDN) is that it can’t offer origin pull at the moment. Not ideal, as we’d like to get it running with a few folders on our site that are frequently updated instead of having to issue staff access keys to upload material to our buckets there. Furthermore, gone are the days of virtual directory listings: instead, users are confronted with an ugly ‘access denied’ message:
AccessDeniedAccess DeniedEDA014F533CAA (…)
We’re considering investing a bit more and moving to EdgeCast, as they offer exactly what we want: origin pull. They also feature more POPs, with a total of 19 online at the moment, and Dubai and Madrid due to be rolled out soon. That’ll give us some great coverage plus the flexibility we desire.
On a personal level, I actually believe that EdgeCast beats the incumbent ‘favourite’, Akamai. Nevertheless, as you can probably tell, it’s entirely a matter of taste.
If you’re an Immediate VPS customer, we’ll gladly provide free advice on CDNs if you send us a ticket with a bit of information for us to make a recommendation with. Remember, nothing beats personal research into what’ll work best for you and/or your business.