Virtual Server Technologies and SQL Server
Recently virtual server technologies have been getting a great deal of buzz in the industry. Is this a technology that I should have on my radar screen? What impacts does this technology have on SQL Server? What can virtual SQL Servers do for me as a DBA? I have been hearing a great deal of positive information, but is there any down side of implementing this technology for SQL Server? Where can I find more information on virtual server technologies?
Virtual server technology has been available for the last few years and has grown in popularity for a number of reasons. As a DBA, it should be a technology that you have on your radar screen because it can probably help you in specific areas.
What are some of the benefits associated with the virtual servers?
- Consolidate many small machines to a single host with many virtual servers that still has the original server name, IP address, etc.
- Ability to create new SQL Servers quickly and in a consistent manner.
- Ability to shut down and move around the virtual servers on the host as needed (virtual server product dependent).
- Ability to have a number of development and test instances that can be easily created and removed based on the testing needs.
- Ability to perform load testing with resources similar to the production environment by reallocating the resources to the virtual server during the testing session and then allocate the resources to the original virtual servers.
- Ability to leverage this technology for disaster recovery purposes.
Do you have any words of caution?
- Capacity Planning - Perform capacity planning to ensure the host will support the virtual servers for a specific period of time (6, 9, 12, etc. months) do not assume that the host will just support all of the virtual servers.
- IO Issues - Systems that are currently IO bound should have the IO issues addressed prior to building a virtual server. Do not assume\expect that these IO issues will disappear with the virtual server.
- Host Updates - If an update (service pack, hot fix, etc.) is needed for the host, the virtual servers may need to be shutdown when the update is installed. Verify with the virtual server vendor.
- Licensing Costs - Using virtual server technology may not eliminate licensing costs. Check with your vendors.
- Hardware Costs - Using virtual server technology may not reduce the hardware costs or monthly lease expenses. Check with your vendors
- SQL Server Consolidation - Although all of the virtual server instances are on the same physical piece of hardware, which is good for the networking folks, as a DBA we typically manage the SQL Server instance. As such, do not cause a situation where you are going to have to manage more instances of SQL Server with the virtual server technology. Shoot for a situation where you are managing the same number of instances or less.
As a DBA should I consider any alternatives to virtual server technologies?
- Multiple SQL Server Instances - One option is to build a number of SQL Server instances on a single SQL Server, but if Windows related applications need to run outside of SQL Server, version control for development and test may be time consuming, so a virtual server may be easier in the long term
- Databases Consolidation to a Single SQL Server Instance - Consolidating multiple SQL Server instances to a single SQL Server instance may be great from a DBA perspective, but the front end application will need to be changed to support the new connection string at a minimum. In addition, keep an eye on security, file shares and SQL Server Jobs to see what types of impacts they will have on the consolidation process.
- Dedicated Physical Servers - Continuing down the path of dedicated SQL Servers can be costly from a power, rack space and operations management perspective, but could be necessary based on security, performance and charge back type situations.
Who is using VM's?
- Many organizations of all sizes and industries have adopted virtual server technologies for development, test and production SQL Servers from a variety of virtual server vendors.
- Many ISP's have adopted the technology to support instances of Windows server for web sites or dedicated applications.
Who are some of the virtual server vendors?
- Check out the virtual server technologies that are on the market to see if they are appealing to your and organization.
- Analyze your environment to determine where these technologies could be beneficial.
- Consider the virtual server alternatives to see if they offer greater benefits than virtual servers.
- Once you have determined the need and completed the analysis, begin the testing process to ensure this solution will work in your environment.
- Check out the following related MSSQLTips:
Last Updated: 2007-02-21
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