October 31, 2009 / 0 Comments
Having worked in data centers for the last four years of my life I know that most servers are grossly under utilized. Burning the power to keep servers online that are utilized, on average, five to twenty percent.
Economics, the way they are today, constantly challenges us and pushes us to find new and creative ways to solve problems. Virtualization allows us to provide consolidation for under utilized servers and “pools” resources to allow systems to burst when they need it. Virtualization, in my opinion, is a very green initiative. In this article I will talk mainly about VMware based virtualization technologies.
So what are the benefits of virtualizing your servers?
- Instant ROI – Servers which were underutilized no longer consume power.
- Ease of Management – Restart systems from a central management location
- Dynamic Resource Scheduler (DRS) – VMware technology provides the capability to VMotion servers from one physical system to another when extra resources are needed. DRS even weighs the “cost” of moving the machine to another host machine.
- Capacity Planner – VMware also has utilities to help you plan your virtual environment based on your site’s resource needs. Simply install a utility and let it run for about 30 days. Once the utility has gathered enough data, you will be presented with suggestions
- High Availability (HA) – VMware offers highly-available services. All of your systems will now have the added benefit of HA at the virtualization layer
So, if Virtualization is so GREEN then what are the downsides?
- Initial equipment cost is high
- Use of fast centralized storage (SAN, NAS) is needed; very expensive
- Systems must match architectures (AMD, Intel) to allow VMotion/HA
- Systems must support Virtualization Technology (VT)
If you can afford the initial expense, virtualization will save you money in cooling, power and equipment maintenance costs in the long run. I believe virtualization is a great tool to help reduce datacenter costs. Please remember there are things that should not be virtualized: large database servers, exchange servers and some application servers may be too disk intensive for your environment’s abilities. Consider keeping these systems as physical servers.
October 31, 2009 / 0 Comments
Ever heard someone use the term VM or VPS? About the only thing they have in common is the V in their name.
A VPS (commonly OpenVZ or Parallels Containers) is a Virtual Private Server and usually runs on what is referred to as a “host node” or the main hardware node. VPS systems allow you to dynamically adjust resources without a restart.
A VM (commonly VMware ESX) is a fully paravirtualized system which all hardware is also virtualized. Many operating systems seem to work the best with paravirtualized systems as the hardware is presented as regular physical hardware.
- Full Paravirtualazation
- Virutualizes at the hardware level- most compatible
- Industry Standard
- Can run Windows/Linux/Suse/Novell/OSX all on the same host
- Cannot dynamically scale resources, VM’s must be rebooted to apply new allocations
- Slightly slower than software-level virtualization
- Cost, expensive
- OS level virtualization
- Fast provisioning
- Dynamic resource allocation, no reboots
- Tighter control of space and inode allocations
- Burstable RAM settings
- Only Linux or Windows VPS systems may exist on a single hardware node
- Price, although cheaper than vmware, still pricey. OpenVZ is a safe free version.
There are many different solutions to virtualizing or “chopping” up the resources for a single, large host system. Our winner was Parallels for their ease of installation, dynamic resource allocation and faster performance. Also keep in mind that if you are virtualizing systems make sure to have a good backup plan and spare parts or on-site warranty. One large host system may provide 20-50 virtual systems. An outage is now multiplied by the systems you have running on top of your hardware node.
October 31, 2009 / 0 Comments
Ever wondered why Postini blocked your email? Luckily Postni provides their “Postini Message Analysis” tool to assist in tracking down pesky false positives.
Here’s how to run your message through their analysis tool:
Login to Google Postini’s web interface at https://login.postini.com/ and release your quarantined message.
Open your message in your favorite email client. View your message headers and copy everything from the top down to (and including) the line starting with “X-pstn-addresses:”
Visit the Postini Message Analysis Tool page and paste in the content we copied in Step Two. Press “Analyze Message”
Review your results and see why the message was counted as SPAM.
Another helpful page is Google’s description for what each custom header tag (added by Postini) represents. See this page for more information.
October 11, 2009 / 0 Comments
Caught up in “cloud” technology? Think it’s useful or just some hype? This post will provide an extensive review of the pros and cons of cloud storage. We’ll also provide a definition of “cloud” storage and the difference between a public and private cloud.
There are a few different types of cloud storage. The main goal of the term “cloud” is to separate and decentralize storage. Systems should be expected to fail, fail often (more often than enterprise class hardware) and be easily replaced when they do. There are many providers of public cloud storage and quite a few vendors which provide cloud storage software so you can start your own cloud.
Public Cloud Providers
Private Cloud Providers (Software)
There are many benefits to utilizing cloud storage. One of the best benefits of using public storage is to diversify and distribute storage across the nation. Utilizing a private cloud allows you to decentralize your storage and possibly speed up largely parallel reads and build fault tolerance into your storage systems. I’ve personally had experience with ParaScale and it seems to work great. The software allows you to build your own private cloud storage system. In testing it has proved to be very fast and efficient.
Utilizing a public cloud can be a bit scary for some. Of course it requires a level of trust and assurance to allow your data to be on a public system. I’m sure most responsible persons will keep copies of their data elsewhere beside a public cloud. Private clouds are still somewhat new and require special software. If the software (or any underlying proprietary system) fails, it will require custom services (provided by the software vendor) to recover the data. Private clouds can be very helpful but we must weigh the benefits against the risks.
Cloud storage has been very successful in both private and public practice. Cloud storage provides cheap and distributed storage for files and can add speed if used privately. This technology is still very new and it must be considered with a “grain of salt” – we’re talking about our data here! In conclusion, Cloud storage technology is very efficient, decentralized, highly fault-tolerant and can offer us many benefits. The only way for the technology to mature is to provide more use and refinement. When cloud storage platforms are fully matured we can place more hope in the “cloud hype.”