Originally Posted by Boadicea
When i say "single point of failure", i'm talking about having 10+ virtual servers go down because one physical server fails. Even if you double it up with failover, you still have a higher potential risk. You're also more open for security problems as one hack (for someone that knows what they are working wth) could potentially get the lot. You also have the problem of one customer running heavy scripts/database searches etc and chewing cpu/memory.
Overall, I'm guessing that our "target clients" are different. I'm working with customers that want good service and you're working with people that want cheap. I've had far too many pepole move over because their "server" ran out of (shared) disk space and their services crash because it ran out of (shared) memory.
I believe you have some fundamental misunderstandings of enterprise cloud / virtualization technology - at the risk of angering you - let me take a moment to try to highlight some features for you specifically in reference to your statements above.
Disk: you wont run out of disk when on an enterprise level san because it will be able to scale out. You also will have predetermined LUN sizes but they will be able to grow with a mouse click. You can also reserve disk for a vm and limit disk for a vm so you dont run out. You can oversell easier through thin provisioning as well if you so choose. Enterprise san is like having many many internal raid arrays in a big array. faster and more resilient.
CPU - you can limit the amount of cpu a customer gets down to the mhz and you can give them a defined ability to burst - software like vsphere will manage the resource for you and will get you the minimum and allow you to use up to what you allow that is available in burst.
memory - you can carve out the min and max they can get
security - you secure the individual vms - no one can hack and get all the vms at once. You also run the box from vcenter which is inherently more secure than at the os level. you will not see entire box compromises like you do with lower level tinkering around vm software.
High availability - you can run ha in resource pools which means those 10 machines you reference can be part of a ha "group" (resource pool, and if one of the boxes goes down, the vms on it migrate automatically to another box - they can go to one box or they can go to the best boxes available based on capacity through DRS.
Scheduled maintenance downtime - its a thing of the past since you can use vmotion to move the running vms to another box without even seeing a reboot.
user running something heavy that will cause problems for others - not in vmware - you can limit and scope the resources they can access.
Bottom line this is a good illustration between enterprise level offerings based on vmware etc compared to amature hour based on things like openvz.
I hope this helps - just post if you have more questions.