DoubleTake vs Clinical Systems


  • Winner of the 2016 Presidential Election

    Hello lovely people of tdwtf,

    I have an issue with DoubleTake and know absolutely nothing about this high availability solution.

    The situation is the following. I work in the cancer care sector on a radiotherapy treatment system and a customer of ours has against our advise put his main oncology database on a server mirrored with DoubleTake. We only validated for clustering. In preparation for a version upgrade the customer tried to perform some OS updates and SQL updates during clincal times while the application was running. We told them not to, but hey... customers. During this process a failover occurred that broke a lot of things within the radiotherapy SQL database.

    I spent hours fixing thousands of lines of SQL by hand, which was well... fun.

    Now, the original server has been rebuilt by their IT and windows updates and patches have been applied to it that are not on the current primary node. The customer would now like to fail back. From my understanding of things, as soon as that happens the second server will be overridden with a copy from the current master node - however, I might be wrong.

    Does anyone know if there is a way to failback and retain the updates or if that is even the default behaviour? I spent some time on the line with DoubleTakes official support today and they didn't seem to want to commit to an answer ... likely because an outage of service would mean a serious negative impact on patient care.

    However, I would still like to know if its doable and if so how. That particular client had a string of mistreatments as a result of database damage incurred during the initial failover, so I would like to avoid that particular level of hell spawn for a second time in the interest of the patients.

    Anyone with any experience of that software here? I debated asking StackOverflow... but I don't think I'd trust any advice I'd get from there.



  • I've never used it but it might be a good question for Spiceworks if no-one on here knows as there seems to be a couple of people using it?

    There is a guide here for failing back with Double-Take: http://www.ctc-g.co.jp/~ctcsp/products/doubletake/availability_user's Guide/Content/RestoringThenFailingBack.htm

    The 'Use Backup Replication Set check box to use the target’s copy of the replication set database for the restoration' option sounds like it would do what you want, might be worth a read (if it's for the same version you have etc...).

    @royal_poet said:

    I spent some time on the line with DoubleTakes official support today and they didn't seem to want to commit to an answer

    Symantec were the same with me on a replication issue, I felt like asking how it's possible to not know how your own bloody software will behave.



  • @Cursorkeys said:

    I felt like asking how it's possible to not know how your own bloody software will behave

    To be fair, in 2015 there are more tools to help developers create software with unknowable behaviors than have ever existed before.


  • Winner of the 2016 Presidential Election

    This is very true. Looks like my day will be testing unsupported crap to figure out what that thing does.


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