You could also just get a dedicated server with a good chunk of ram. Say, 32gb or the new 64gb one. Then install XEN or KVM on it and run your own VPS farm instead. It'll save you $800-1600 USD/month in the long-run once you fill up the whole box with VPSs.
Another thing to note is that the new 64gb instance trucks a hexacore (6) core CPU and includes hyper-threading. Now, correct me if I'm wrong, but I believe this means you can run 12 virtual cores in your XEN/KVM instances with this, instead of only 1 which is provided by the Hetzner VPS's. That's quite a difference.
With my 32gb box (which is a quad core with hyper-threading) my XEN instances can spin up to 8 virtual cores, according to the (h)top utility.
The chances of that happening are low anyway. I believe someone reported their server was running smooth for 3 years with only a single _minor_ downtime. Also, I doubt that an app that runs on a VPS is as important as one that requires a whole dedicated server. But yes, if a box happens to fail, how slim the chance may be, then your site is offline, just like Amazon EC2 that was offline for 3 days iirc even though they have multiple availability zones per region.
Also, running 3 dedicated servers for redundancy still isn't expensive when you compare it to traditional VPS/EC2. However, you do have to do everything yourself of course. Tbh I feel that people always tend to worry too much about "downtime" or "failing boxes" while the reality is that most people don't ever experience huge downtimes. If the app is really _that_ important then you're likely making some good money to justify paying for more expensive solutions and there wouldn't be a reason not to do that.
Wouldn't the risk of that be exactly the same as the risk of a host box dying at for any VPS product anywhere? Specifically I'm sure Hetzner is running their VPS product on the same boxes, since one of their methods is to have a very standardized, custom designed box (like google does).
The good VPS providers have fail over hosts so that they can move your guest if the primary host is experiencing issues (e.g. RAID degradation). Linode have this for example (I know because one of my 512MB guests got moved recently).
Edit: Leaseweb (who are on a VMWare stack) also offer something similar via Vmotion
As many as you like, if you don't mind overcommitting the cores. CPUs overcommit quite well - it's when you start overcommitting RAM that you get into trouble.
But surely you'll have a hell of a lot less CPU power than, say, 128 of Linode's 512mb virtual servers, meaning they would have much worse performance if fully used?
That would depend on the type of CPU Linode is using. What the CPU's frequency is, the amount of cores, whether it has or does not have hyper-threading technology.
The hyper-threading technology is a pretty cheap way to add more virtual cores to your VPS's which is great. One thing is for sure and that is that Linode provides you 4 virtual cores and not 12 per VPS. But, that of course doesn't mean their CPU is better or worse. But, if you can run 6 cores at 3.8ghz, or 12 cores at 1.9ghz then I wouldn't worry too much about not having enough CPU power for your virtual private servers.
If any CPU-overcommitted VM system has guests which all want 100% of the CPU, they'll all suffer. No two ways about that. I don't know what hardware Linode put their 512MB instances on, and I don't know their overcommit ratio. 128 is more guests than I'd put on a 64GB host, though.
If your typical load is actually at 100% CPU for the majority of the time, I'll go out on a limb and suggest that VPS might not be the best bet anyway.
How hard is Xen to configure and maintain? I like VPSs because they're mostly hassle free, and all my projects are separate and isolated. It seems like running all my projects on one box would be a massive headache!
I did a light benchmark of their 512MB VPS[1] which is insanely cheap. The only things that change when moving to the 2GB VPS is RAM, hard drive space and total data transfer. The CPU remains a single core and the same speed according to [2]. It's possible there's less contention but you'd need to find a benchmark for the 2GB VPS to know for sure.
If you're after any specific benchmarks give me a yell and I'll see if I can provide one for you.
I and several of my clients use quite a few of those and I'm very happy with the performance. IO performance is very good (especially for a virtualized system) for example apt-get update / upgrade takes less time on one of those than it does on a dedicated root server of mine (Core i7 Quad, 8 GB Ram, 7.2 kRPM SATA).
Alvotech (also German) offers roughly the same specs for about half the price, after a 10€ setup fee [1]. Although I haven't yet pushed these virtual servers to the limit in any sense, I can say I'm a happy customer.
That does look like a very nice service, but it seems to be much lower-end, not "roughly the same". The CPU is an in-order 1.8GHz Atom, which is not roughly the same as a superscalar out-of-order Athlon 64 or Core i7, and their RAM tops out at 4GiB, which is not roughly the same as 64GiB.
i have their 10 euro plan for running tamahatta.com, dont have any traffic but the site has'nt gone down for the last 2 and a half mth. ( which is when i took it)
Their 2GB plan is 3x cheaper than Linode…and you get over 4x the data transfer! Does anyone know how the performance compares?