If you're actually running a business, then redundancy is the way to go, not spending more on real hardware. With a VPS, you're able to achieve redundancy fairly easily, provided you have multiple datacenters available (Linode does). Without some sort of failover, a dead server means downtime whether you're dedicated or VPS.

Also, Linode's SLA may be 99.9%, but I've experienced with two businesses, using Linode over the course of four years, about 45 minutes total of downtime (on any given server, not our entire infrastructure). I'd much sooner take years of past experience showing incredibly good uptime over a piece of paper meant to limit liability.

I believe Linode is an excellent choice for small-medium sized online companies.

It depends on the stage of the business. For a small business that might be running off of one or two VPS's, you're probably much better off paying a few hundred dollars a month for a machine that is up 99.99% of the time instead of 99.9% of the time than to spend significant engineering time trying to setup database replication and failover (and either relaxing consistency or adding significant latency to your site) in the hopes of getting an 99.999%.

This is especially true given that more often than not, within the first 5 times you use it, you'll experience some bug in your HA setup that leads to some complicated, slow-to-diagnose-and-fix failure.

"... and they tend to scrape by just barely exceeding 99.90% [uptime]"

Wow. That sentence makes 99.9% uptime sound really shitty.

It is shitty for infrastructure. 99.9% server uptime means your site might be down for about 44 minutes per month, through no fault of your own--i.e. that does not even take into account scheduled downtime, application problems, DDOS attacks, etc.

really, you don't count scheduled downtime and DDOS attacks in your uptime?

Might as well stop counting sysadmin screwups and hardware failures, at that point. 100% uptime! except when we're down.

I do count scheduled downtime and DDOS attacks in my uptime, which is why I wouldn't tolerate 44 additional minutes of downtime from my infrastructure provider.

yeah, my argument is that scheduled downtime (scheduled by the infrastructure provider) and ddos attacks (against the infrastructure provider or other customers of the infrastructure provider) should count against the infrastructure provider's uptime.

The current balance of power is tipped, right now, so hard in favor of the attackers that if anyone wants to take /you/ out, well, it's pretty difficult (read: expensive) to stop them, and if you are some $20/month customer, your upstream is probably going to just finish the job and cut you off... but if the guy next to you gets attacked and you are collateral damage? You should count that against your service provider. There are usually things we can do (as service providers) to limit collateral damage, even in the cases where we are unable to protect the target. If nothing else, providers who tend to tolerate sites that get attacked often, well, they suffer collateral damage from attacks, generally speaking, more often than sites that are less tolerant. It's sad, really 'cause sometimes the targets are not doing anything really wrong, but you've gotta protect your network.

There is some advantage of scale here, too... The DoS that is hardest to fight is the pipe-filling attack. If the attacker can fill your upstream port(s), then there isn't really much you can do, besides blocking the target at your upstream, (I mean, assuming the source is random, as it often is.) The larger your upstreams are, the more you can absorb before you have a choice between cutting off the target customer and having all your customers cut off.

Do you consider a 45-minute outage once a month to be acceptable? Maybe for the price, it is.

Well, if we are being pragmatic it sounds totally acceptable for any kind of business.

Except maybe if those outages hit them at the worst possible moments of the month (just before a major announcement or something).

Now, managers would froth at the mouth hearing 45 mins/month is acceptable. But those managers are idiots.

I haven't seen any major site that didn't have those (and worse) outages.

5-6 hours a year? Heck tons of sites had those. AWS had them (and thus Heroku had them), GAE had them, Twitter had them, Tumblr (well they had one-two orders of magnitude more), etc.

45 mins a month represent lots of lost revenue to you? Really? If you're not Google or something, then what exactly do you do?

Shouldn't that be like 0.1% of your revenue? And that IF you sell online and IF we assume customers aren't gonna come back. Heck, you lose more because of random fluctuations in buyer preferences than that.

Depends how you look at it. A minute and a half a day? Doesn't sound too bad when you say it that way. A 3-hour outage every 4 months? My cable company can barely do that.

The problem is outages tend to be for prolonged periods and not spread evenly across the month. A minute may not seem like a huge deal, but 3 consecutive hours is really going to piss some people off. If you run a business, it's completely irresponsible to provide such a low level of service to your customers.

0.1% downtime is about 45 minutes per month. Depending on how it's distributed, that can be extremely annoying.

Well, these days it is. You want five nines (99.999%) on mission-critical applications.

Five nines will cost you a lot of money.

it's usually achieved through luck, not engineering.

Could you buy two cheap VPSs from different suppliers? That way you'd have redundancy and save money?

I've been looking at cheap VPSes over the last few months, as I don't really want to spent $20/mo on Linode anymore for a static site and VPN. I've tried a number of different providers, and they've all had issues.

Things I've experienced:

- being rebooted without notice

- poor performance (IO and / or CPU)

- provider being DDOSed

- provider moving to a new DC and telling people not to give out IPs (???) due to being DDOSed

- hosts running old virtualisation software which doesn't support recent versions of Linux, so I'm can't use an OS newer than Ubuntu 10.04

- provider being banned by PayPal then suspending my account being I couldn't pay then

- provider going out of business

I liken it to poor quality manufactured goods. Take the Android tablets you can get for less than $100. If you can afford it, you would never buy one just to save money, because it is much less hassle to spent another $100 and get something that works well.

It just isn't worth it, especially not for a business. I would love to see someone who can make a proper fault tolerant system that works on these type of machines though :)

Depends on your site, and how trivial it is to balance it between two locations, keep it in sync, add in a way to switch over, etc.