InfoWorld review: Virtualization for development and test

VMware, VMLogix, Surgient, and Skytap lab managers ace virtual machine configuration, deployment, and teardown, with some key differences in features and ease

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InfoWorld review: Skytap Cloud
The Skytap product, whose name changed during this review to Skytap Cloud, is an entirely cloud-based solution. For a monthly fee based on projected number of resources, you're given a login that enables you to build and run virtual machines and configurations on Skytap's cloud. The cloud itself is hosted by Savvis, a $1 billion market cap provider of corporate infrastructure services. It is tempting to compare Skytap with Amazon's EC2 cloud service, but in reality there is no comparison.

For starters, Skytap runs on VMware hosts; unlike EC2, which only recently announced limited support for Windows, it lets you run all forms of Windows machines, from old versions to 64-bit heavy lifters with eight cores and 8GB of RAM. It also runs just about every other major operating system. Skytap facilitates construction of your own template library by having templates of all major machines available for retrieval from its central vault. If you grab a Windows machine, you'll need to enter the 25-character license key the first time it starts up; then you're good to go.

If you already have your own virtual machines, you can upload them to your library. Running Skytap was trivially easy and intuitive. Weeks after the half-hour demo, I was still able to log in and successfully run around the system, tending to all the standard tasks. Features work as expected, the interface is both intuitive and attractive, and users are immediately productive.

The cloud environment is nicely leveraged by Skytap. It's possible to configure the lab manager's IP configuration to be an extension of an in-house segment so that you can make the virtual machines available as normal machines to users. This is safe, as IP addresses are not exposed to the outside unless you explicitly configure them for public access and assign them one of the IP addresses in your public pool.

The linked clone issue is handled differently by Skytap. Rather than use VMware's approach, clones are not linked. Rather Skytap drops to the OS level and simply copies the disk image of the VM in its entirety. The cloud storage is optimized for disk I/O, and the company claims that this approach can be as fast as VMware's cloning. Given the impossibility of comparing like to like, this could not be verified -- but I remain skeptical.

The Skytap console below shows a configuration of three machines running on the Skytap Cloud. (Click image for closer view.)


Pricing is favorable when compared with standard cloud options. The base enterprise pricing comprises 50 virtual machines, 5TB of storage, 1TB transfer, 10 IP addresses, 50 users, 1,000 VM-hours, IPsec, VPN, and training for $2,400 per month. VM time is measured by the minute, with no rounding for fractions of an hour. Sites can have their cloud custom branded so that there is no evidence the systems are running on an outside platform. An express plan for small businesses or tire kickers offers the full set of features for five users, five virtual machines, and 500 machine hours for a mere $250 per month.

Overall, I was very impressed with Skytap. It's easy to use, works well, and is favorably priced. My principal complaint is that the company reserves a four-hour block of downtime twice a month (on Saturdays). It sends email reminders of these time slots well in advance. As the hour approaches, a notice appears across the admin console, but when the moment finally arrives, the virtual machines are shut down without further notice. I don't like this downtime window, as it precludes longer-running projects, and I would prefer more warning rather than an abrupt shutdown.

Otherwise, however, Skytap is an excellent solution. I expect the company's offering points the way to the future for lab managers.

Read more InfoWorld reviews of software development tools:

This article, "InfoWorld review: Virtual lab managers face off," was originally published at Follow the latest developments in software development and virtualization at, and get a digest of the key stories each day in the InfoWorld Daily newsletter and on your mobile device at

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