Are Virtual Dedicated Servers Worth The Cost?

xtremex asks: "I just had an online conference with a company called Ensim and they have made an appliance that takes all the servers in your data center and chops them into 'virtual' dedicated servers, so instead of a dedicated server client wasting 50% of his space and server power, it'll take one server and issue a percentage of processor power, memory and disk space, each virtual server having their own root password, etc., and a Web based control panel for both resellers and owners...this thing got me salivating..until the told me the price..$25,000. I almost fell off my chair. It looks REALLY good, but is it worth $25,000? They even offered to come down and install it and I have the unit for 30 days free..Does anyone know about this amazing product? Is it worth the price?"

Comments

Awful lot of money for such an old problem

[bgalehouse]

Unix people have been building time sharing systems for a long time. For 25k, I'll bet that I can get pretty close to this sort of thing. Let's take an inventory of what you really need.

1. You want each client to run and admin their own webserver.
2. You don't want each client to be able to affect the others. This means no rampant interfering resource usage.

Now, lets talk about how one might do this using off the shelf stuff.

1. Two ways to run multiple indepentenly admined web servers come to mind:
   • The new FreeBSD kernel supports the jail syscall. This can attach collection of processes to a particular ip address. I rather suspect that this is exactly the sort of thing that it is meant to be used for.
   • On linux, you can permission individual ports. Each client runs their webserver on a different port. Use ip masquerading to redirect connections to diffent ips (port 80) to different ports (localhost).
2. Unix timesharing systems have been hit with all sort of internal dos attacks. My personal favorite is the shell script which does nothing but call itself in an infinite loop. Hence the creation if killall. All of these attacks (which can be negligence as much as anything intentional) have defenses. Unix is meant to be multi-user, even if we forget in the PC-laden age. We have:
   • Quotas - x% of the hard drive, coming right up.
   • Process limits - With not too hostile users, it shouldn't be too difficult to keep their web servers from running away. Note that csh is the ussual interface to this functionality.

So what do you really get for your 25k? My guess is a little bit of convenience. Maybe a bit of transparency to your users - don't have to tell them it is a shared box if you replace login to use per ip password file, could rewire the reboot command to do a kill for the users in question and rerun 'their' /init.d scripts, etc.

And if this package doesn't take off and becomes unsupported... then where are you? It doesn't quite sound like the sort of thing which will work with the next version of whatever OS it is for. Unless it is a colletion of perl and shell scripts (about what I would use), in which case you could patch it up if necessary. Do you get a source code license for your 25K? Is their customer care any good?

It might be worth it, if they make it truely easy to multi host, and give you a source license, and you are short of rack space and/or using really expensive boxen. But I wouldn't bet on it.

Ensim ServerXchange

[Paul Menage]

Ensim ServerXchange effectively costs $250 per machine: the $25,000 box is a provisioning box which can provision up to 100 other machines. Each of the provisioned machines can then be chopped up into private servers with a percentage of memory, space and processor power. You also get:

• an integrated suite of web- and Java-based applications providing control and management for the service providers, their resellers, and their users;
• a large number of applications and application suites that can be installed en-masse on private servers with just a few mouse clicks.

To answer questions raised in other comments:

What's the difference between this and installing VMware for $329?

Even though an Ensim private server appears to the applications running on it to be a dedicated server, it runs in the same operating system as the host. This means that it can take advantage of services provided by the OS with much less overhead than VMware, in terms of both CPU and memory usage.

How is this different than traditional load balancing / clustering / virtual web hosting and the like? Where is the real benefit?

A private server is a fully featured virtual machine and provides a lot more flexibility than traditional web hosting. It is cheaper than a dedicated server (both for the ISP/ASP and the customer) while providing guaranteed resource allocation.

...there is absolutely no way in modern operating systems to allocate CPU space to a group of processes.

We can do it :-)

Unix timesharing systems have been hit with all sort of internal dos attacks. My personal favorite is the shell script which does nothing but call itself in an infinite loop.

If you do this on an Ensim private server you will only hurt that private server itself. Other private servers running on the same box will not be affected.