Wandering Thoughts archives

2007-07-27

How big is the Slashdot effect?

Recent events have made me more curious than ever about just how big the Slashdot effect is. If you get linked to by one of the popular sites like Slashdot, Digg, or reddit, how much load are you actually going to get hit with?

(Correspondingly, if you are trying to make sure a web application can stand up to a Slashdotting, how much load do you need to be able to handle?)

Unfortunately, good current data is hard to come by; most of the reports on the details of the effect are old, and most of them don't include the numbers I'm most interested in. Most people only report their total hits over a relatively long time, but the numbers that matter for performance tuning are the peak concurrency and peak hits per minute or per second.

The best recent sources I've dug up so far are here (from 2006) and here (from early 2007). They suggest that the Slashdot effect is good for a few hundred pageviews a minute over your busiest hour or so, but don't say anything about the peak; other reports suggest between 25 and 50 requests per second (1500 to 3000 a minute) at peak, but no one seems to have a solid number.

(Remember that a single pageview may result in more than one HTTP request, since it needs to get all of the graphics, stylesheets, JavaScript, and so on.)

Another useful tidbit to know about the Slashdot effect would be how much extra traffic your other pages will see. (My guess is that almost all of the traffic will go to the page that got linked and only a few visitors will go look at the rest of your site.)

PS: if I ever get hit with the Slashdot effect, I promise a full report. Not that I expect it to happen. (Yesterday is the closest I've come to that sort of thing; although a couple of entries did appear briefly on programming.reddit.com, it was without serious effects on my traffic levels.)

web/SlashdotEffectSize written at 23:24:09; Add Comment


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