Akamai Diversity

The Akamai UK Blog

Enhancing customer experience through effective image management: Part Three - Allowing for problems

Missed the rest of series? Click for Part 1 and Part 2

With the best will in the world and great planning, even the most stable websites occasionally suffer an unexpected outage. Your web operations team is charged with managing the risk of these unforeseen situations and they need to recognise that images are just as vital to your disaster recovery and business continuity plans.

As well as planning, they also need to understand the Mean-Time-To-Repair (MTTR). To put this into context, a customer of ours was once under a volumetric security attack making their primary datacenter inaccessible. The disaster recovery plan was initiated and they proceeded to failover to the backup data centre. Unfortunately, because of all the mobile optimised images and the many small files, it would take eight hours to restore from tape backup. That's a long time for a website to be down, and plenty of time for customers to move onto a competitor's site.

Images consumed for the web tend to be smaller than a single iNode on disk. The overhead of file system metadata can dramatically impede the fastest RAID array.

 Key factors to consider in your image management strategy include:

  • Including image restore time in your disaster recovery and business continuity plan.
  • Prioritising pristine images (those before any resizing or automated transformation)
  • Comparing backup-restore time for all images against the cost of just in time generation of derivative images
  • Utilising multiple caching layers in your architecture, including a CDN to reduce the demand while

Finally, an image management strategy should also account for bots - both good and bad. Some bots are good for business because they can drive search engine traffic. Other bots scrape and steal your image content and use it for other objectives.

Just as with a mobile image strategy a bot image strategy can help optimise costs related to delivery. Bots are increasingly sophisticated and having the wrong strategy can quickly turn into a game of cat-and-mouse. A few key considerations to include:

  • Classify types of bots that are clearly good for business (SEO crawlers), clearly bad (scrapers on AWS), or unknown - acting differently depending on each bot type.
  • Optimise the performance for search bots by delivering smaller resolution images to improve website performance for search bots
  • Reduce delivery costs for "bad" bots by delivering placeholder image (1x1 white pixel) or using a blurry low resolution image. The goal is to send as little data as possible without causing the bot to detect the counter measures.
  • Analytics - track image consumption by friendly and nefarious bots alike to tune and tweak your countermeasure strategy.

The success of your brand and online presence depends on a good image management strategy. This strategy should address the needs for your internal content creators, your customers, particularly those using mobiles, security risks, operational risk management and even manage costs from bots. The objective of these strategies is to utilise images to increase revenue without causing increased operational costs.