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From the Chief Technology Officer at Marathon Technologies

Jerry Melnick

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Q & A for the February Webinar: Practical, Affordable High Availability and Disaster Recovery for a Tough Economy - Featuring Forrester Research

We had a lot of great questions during the Q & A session of our February webinar with Stephanie Balaouras of Forrester Research. We’ve posted the questions and responses here on our blog for everyone’s benefit.

Questions from the webinar:

Q: In the architecture two "mirrored" VMs are shown which are connected. Does that mean that you have to install 2 application VM servers or do you have to install just one and Marathon makes the second?
A: You only need to create one application VM. After this is created, you can use everRun to protect that application. As part of the protection process, everRun creates a “cloned” instance of the application on the second host. The instance is completely identical to the original, with the same identity, MAC address, resources, etc. It is this redundancy created by everRun that protects the applications.

Q: In the Marathon license there is HA and FT. In which are the levels 1-2-3 available?
A: Levels 1, 2, and 3 are available in a single solution called everRun VM and any level of protection can be enabled on a VM. everRun VM level 3 protection will be available in Q2.

Q: The licensing question you just answered seems different from what you used previously. You previously only had to license the VMs OS in a fully protected system. Please explain.
A: Microsoft licensing requires a valid Windows license for each side of the protected VM. Using Enterprise Edition can reduce the number of licenses required. Please refer to Microsoft licensing terms for specific details for your environment.

Q: How does the software communicate between disparate storage NAS to DAS, SATA to Fibre Channel?
A: everRun does not limit you to needing matching storage requirements on multiple hosts. Communication between hosts is done through Availability Links (A-Links), which are private networks between each host. everRun handles the mirroring at the host level, passing I/O through XenServer to write to the disks. The type of disk or connection is not relevant.

Q: How does this compare to VMWare's SRM & VDM products?
A: VMware SRM provides a mechanism to restart a VM on an alternate host, however it relies on other storage mirroring solutions (often within the storage system) to perform the mirroring. SRM does not move data or provide a comprehensive HA or FT solution.

Q: Is the product host based or a fabric based solution?
A: everRun VM is a host based solution, with a minimum of 2 hosts required.

Q: Do you need to keep a warm copy of the applications at the DR site?
A: During the protection process, everRun takes the chosen VM and clones it to the designate secondary host. This creates a complete and identical instance on the secondary host. everRun maintains these two synchronously so that they are always identical. everRun’s unique architecture exposes these two mirrored instances as a single entity; there is no need to install, manage, or update both sides, only the one single instance of the OS/application. Should the entire ‘primary’ host fail, the ‘secondary’ host will immediately start the cloned version. It comes up with the same IP address, hostname, and MAC address of the primary so that there are no client-side, DNS, Active Directory, or other infrastructure changes required.

Q: Is the DATA synchronous like SRDF or near synchronous?
A: everRun performs synchronous mirroring of the entire Windows environment, including the OS, application, and data.

Q: How does this compare to products like RecoverPoint/Replistore, InMage, Neverfail, Falconstor etc?
A: These products are disaster recovery products intended for long-distant asynchronous data replication and failover. everRun availability solutions provide true availability in a comprehensive and automated manner. Marathon also offers DR solutions for long-distant protection. Disaster recovery and availability are mutually exclusive in most cases and should generally be considered separately. They are complimentary more than competing solutions.

Q: What is the software support plan? What are the recurring costs for your product year to year?
A: We offer a Premier support plan or a Basic support plan. The only recurring cost year to year is the cost of support.

Q: What are the operating system requirements, how many copies of the OS do you need?
A: Each Windows environment is mirrored to a secondary host, requiring a second Windows license. Using Enterprise Edition of Windows allows for fewer licensed copies. Please refer to your Windows licensing terms for specific requirements.

Q: Regarding the 10ms sync time, what happens if that time increases to say 20ms due to network traffic?
A: If the latency increases beyond our requirement the paired systems may assume that one system is down and redundancy may be lost. In a properly configured environment the application should remain running while the secondary system is no longer maintained in a redundant fashion. Once the latency returns to within spec, the systems will re-sync automatically and return to a fully redundant state. Typically the application is not impacted.

Q: What are the bandwidth requirements?
A: Best practices state 155MB link between the two hosts. For local systems a simple crossover cable between the two systems is sufficient. When separating the systems the 155MB requirement becomes more relevant. This number can vary depending on the applications being protected and the amount of data being managed.

Q: Do you have instances of numerous geo-available solutions with specific applications?
A: Here are two examples:
MAN AG success story with everRun SplitSite
Chester County, PA success story with SplitSite

Q: Is windows Server 2008 VM supported? If not, why?
A: Windows Server 2008 64-bit will be supported in Q2 of this year.

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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.