DealNews: Scaling for Traffic Spikes
Last year Dealnews.com unexpectedly got listed on the front page of yahoo.com for a couple of hours. No matter how optimistic one is, unexpected events like these can take down a regular website with almost no effort at all. What is your plan if you get slashdotted ? Are you ok with a short outage ? What is the acceptable level of service for your website anyway. One way to handle such unexpected traffic is having multiple layers of cache. Database query cache is one, generating and caching dynamic content is another way (may be using a cronjob). Tools like memcached, varnish, squid can all help to reduce the load on application servers. Proxy servers ( or webservers ) in front of application servers play a special role in dealnews. They understood the limitations of application servers they were using, and the fact that slow client connections means longer lasting tcp sessions to the application servers. Proxy servers, like varnish, could off-load that job and take care of conten