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PlateSpin Authors: Greg Schulz, RealWire News Distribution, Elizabeth White, John Gannon, Jerry Melnick

Related Topics: PlateSpin Journal, Citrix Virtualization Journal

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Q & A for the June 24th Webinar: SQL Availability – Protecting Your Database and Applications

We had a number of questions during the Q&A session of our June 24th webinar with Stephen Wynkoop, founder of SSWUG.org. I’ve posted the questions and responses here on our blog for everyone’s benefit. This webinar was recorded in case you weren’t able to attend, click here to view the webcast!

Q: Does everRun require a SAN?
A: It doesn’t require a SAN. We can also mirror storage between two different systems, if that’s what you chose to do. A lot of our customers do that, either locally or separated geographically. We can support a SAN in multiple ways. We can support a SAN where you have a single copy of the data. And both servers will connect too the single copy of the data. We also support a SAN where one of the servers is connected to that SAN and the other server has its own storage and we can mirror between that. A lot of our customers are using that option to provide data protection and fault tolerance at the data level. We can use different types of storage on either side.

Q: With your SplitSite product, are there distance requirements?
A:
There are no pre-determined distance limitations – it’s really the latency and bandwidth requirements that determine the distance that can be supported.

Q Does everRun work with Exchange 2007 as well?
A:
Yes it does. everRun supports any Windows application without requiring changes or customization.

Q: Does everRun work with iSCSI?
A:
We have an agnostic approach to storage as well. Pretty much any type of storage will work. iSCSI, fiber, direct attached, etc.

Q: What are the requirements between the paired local servers?
A:
A gigabit Ethernet connection with crossover cables is usually used between the two servers.

Q: What is the performance impact of using everRun with SQL?
A:
Our preliminary testing has shown that the overhead is very small. There are variance rates depending on the servers and applications that you are using, but the impact has in general been shown to be very small.

Q: How does everRun handle the mirroring of data that’s loaded in the memory?
A:
With our level 3 fault tolerance, we actually mirror the memory and CPU between the two systems, so they are running in lockstep. This provides a 100% uptime solution. Our everRun software makes sure that the memory and CPU state are mirrored and completely synchronized between the two servers at all times.

Q: Does everRun work with SQL 2008?
A:
Yes. everRun supports any Windows application without requiring changes or customization. Because everRun resides below the operating environment, we are protected underneath that. We have a number of ISVs that use our software with their applications and they use us because they don’t have to make any changes to their software. It’s not tied into the application, and doesn’t need to be “cluster aware” or anything similar to that.

Q: Does everRun work with the free XenServer?
A:
Yes, everRun VM for XenServer supports the free version of XenServer as well as Essentials for XenServer Enterprise and Platinum Editions.

Q: How would you tackle a shift from a single server to an everRun setup to have minimal downtime during the changeover?
A:
It’s pretty straight forward. You could buy new servers if you wanted to refresh your hardware. Then you would perform a P2V migration. There are tools like PlateSpin to help you do that. It’s a standard migration process. If you wanted to use your existing server, you could buy one additional server and pair those up. We also offer migration services if you want additional help with the process.

Q: If using everRun with SQL Server, is the secondary server available for query/reports by other processes?
A:
It‘s not because the two SQL environments have the same identity and exposed to the network as just a single server instance. Since they both have the same identity,you can’t access one by its production identity and then the other. They look and act as a single environment. They have the same MAC address, host name, and IP address. If you make a change, it happens to both of them.

Q: In a SplitSite implementation, if one hardware platform fails and the backup is used, how is the data re-synchronized once the primary hardware is available again?
A:
everRun is completely automated, including the recovery process. When you have a failure and get that system back online, everRun will automatically synchronize the two systems to be identical again. There’s no additional work to do the syncing, it’s completely automated.

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More Stories By Jerry Melnick

Jerry Melnick (jmelnick@us.sios.com) is responsible for defining corporate strategy and operations at SIOS Technology Corp. (www.us.sios.com), maker of SIOS SAN and #SANLess cluster software (www.clustersyourway.com). He more than 25 years of experience in the enterprise and high availability software industries. He holds a Bachelor of Science degree from Beloit College with graduate work in Computer Engineering and Computer Science at Boston University.