Well, this site is at a crawl now because the panorama I assembled of San Francisco in 1971 is on the digg.com front page. If you haven’t seen it before it’s on the San Francisco page, the panorama of SF from the top of the Bay Bridge in 1971.
My hosting company, Defender Hosting/PowerVPS, has been kind enough to do a temporary upgrade of my server capacity to their top level, though the site’s response is still poor. This is something that virtual hosting can do that you can’t as easily do with dedicated hosting, though virtual hosting has its own costs, mostly in wasted memory.
I think it would be nice if virtual hosting companies sold this “bump” ability as a feature. When your web site gets a lot of load from a place like digg or slashdot, this could ideally be automatically detected, and more capacity made available, either free for rare use as a bonus, or for a fee. Most site owners would be glad to authorize a bit of extra payment for extra capacity in the event that they’re subject to a big swarm of traffic. (The only risk being that you might pay for capacity when under a DOS or spam attack or when being used by crackers or spammers.)
One place this might happen well is in the Amazon ec2 service, which I have yet to really try out. EC2 offers a cloud of virtual servers on demand. In this case, you would want to have a master controller which tracks load on your server, and fires up another virtual server, and then, once it’s up, starts redirecting traffic to it using DNS or proxy techniques, or both. If a web site is highly based on an SQL server, all the copies would need to use the same SQL server (or perhaps need an interesting replication strategy if not read-only) but making SQL servers scale is a well-attacked problem.
Has anybody done this yet with EC2? If not, I expect somebody will soon. The basic concept is fairly simple, though to do it perfectly you would need to do things like copy logs back after the fact and redirect any pages which want to write data to the local server to a common server if one can. For a site with static pages that don’t change due to user activity, such replication should not present too many problems.