Cloud vs traditional iSCSI, xen, drbd, etc

Are you asking if you could setup a fault tolerant cluster locally with open source tools cost-effectively, compared to purchasing cloud instances from a 3rd party?

I think it depends on how good you are :-)

A major benefit of outsourcing is that they specialize in the hardware plumbing and fault tolerance, so they could be much more efficient at it.

One day everything may be in the "cloud". There are a few things stopping me from moving the majority doing so yet:

• Our corporate email server has gone down less often then my personal gmail/gcal account.
• Having servers locally gives insight into failures; appose to occasional updates from a provider during an outage. Even if it only gives a sense of control (ie, you couldn't fix it faster), that sense can be important.
• I've done the math for a few of our services; we still come out cheaper
• Many services are still valuable during an internet outage, if you have local users.

That said, as we're rolling out new services, I'm evaluating 3rd parties more and more regularly.

These items may or may not be applicable to you, its really dependent on the application.

If you're asking about using UEC locally versus Zen; local UEC is just a system built around KVM virtualization. I can't say which is better. You could ask "I need feature X,Y, and Z; should I use UEC or roll my own zen?"

Agree with all that was previously stated. In addition you should look closely at FC SAN storage versus iSCSI. As a Data Center, our customers have tried several iSCSI systems. Most have had real problems. Corrupting databases, incompatibility with switches, Ethernet Bonding, and driver issues. The FC SAN systems have all worked with little to no problems.