Hosting: someone please explain me this 95% percentile thing...

Chances are that one day will be in the 5%, but yeah, I've always thought it seemed a little unfair.

No. Essentially, the top 5% of the "spikes" in traffic during the month are ignored.

The 95th percentile is a widely used mathematical calculation to evaluate the regular and sustained utilization of a network connection. It is commonly used among all major internet transit and peering networks, as well as datacenters and ISPs for both capacity planning and/or calculating usage. It roughly means ‘for most of the time this was the throughput on the line’.

The 95th percentile is a good number to use for billing as it can allow the customer throughput bursts without additional financial compensation. Basically the 95th percentile says that 95% of the time, the usage is below this amount. Conversely, 5% of the time, usage is above that amount.

There are important factors to percentile calculation:

Sampling interval, or how often samples are taken (called also "data points").

A percentile is calculated on some set of data points.
Every data point represents the average bandwidth used through the sampling interval, calculated as the number of bytes (or KB/MB/GB etc.) transferred divided by the sampling interval length in seconds (effectively representing the average utilization for single sampling interval). The number is expressed in a data transfer rate as bits per second (kbit/s/Mbit/s/Gbit/s).

95th percentile is a fucking scam... No large mainstream networks use it... I would NEVER pay on 95th percentile - trust me, you'll end up paying much more

what i don't get is: AWStats or Webalizer show i used for example 90 gb traffic - and i get billed for 400 or 500gb. that would be only explained by what i wrote in my initial post - cause i always have a couple of days with traffic spikes a month

Well 5% of 31 days, is 1.55, so that is how many days will be take off the top, then the next highest day will be what is used for the 95th percentile... so it's the highest day after the top 5% has been removed...

It's a sham, unless you have steady usage, which is rare

that would explain it pretty well

If it's your content store that's doing it, then 95% will get you burned.

You're doing huge transfers for short periods, but most of the time your connection is sitting idle. You're going to pay the whole month as if people are downloading their zips all the time.

That sounds messed up. It would be interesting to see your mrtg report(s).

With lower bandwidth amounts, you are better off paying by the gig, or flat rate (un-metered).

Fuck I hate people who simply try and sound smart.. it's obvious to everyone else when people do that, and it just makes you look like an idiot

I like Poo

Or the hosting companies could just do the common sense thing, and charge per GB, like everyone else in the world. They offer service, you pay for service used. Not this bullshit...

It isn't always bullshit. There are essentially 3 billing methods; per gig, flat rate, and 95th (or 98th) percentile for a reason - everyones needs are different.

Per gig is fine for lower bandwidth requirements. Flat rate is great for people that want a known set cost, and 95th percentile is typically better for those consuming large amounts of bandwidth that may still need to burst above and beyond "the norm".

look smart by pasting http://en.wikipedia.org/wiki/Burstable_billing grab your self a happy meal, you could use it.