Multiple instances on a single server; looking for opinions

  • I recently took on a job that asked me to evaluate all of their servers and come up with a hardware replacement plan. There are multiple 2005 servers on old hardware. The highest memory in any machine is 4GB. They have similar databases on multiple server because of client demands. I want to consolidate all of the machines to one and upgrade everything to 2008 R2 Enterprise. By contract they have been asked to separate two of their clients onto separate hardware leaving me in a bit of a bind. My solution is to create multiple instances of the database on one server and partition off the data in separate RAID 10 volumes on an attached disk array. The array has two controllers with a total of four channels and a capacity of 24 disks. The server I have picked will have an eight core sixteen thread processor with 128 GB of RAM. The disks, backplane, and controller on the array support 6Gbps IO. My plan is to create four RAID 10 volumes, one each dedicated to the two clients and the other two to the rest. If asked to expand another client to dedicated equipment, I would then suggest adding another array to the mix. Also, I plan to have a duplicate setup using database mirroring as failover. The servers will be connected via a 10GB network. Now with all that background, which I hope wasn't too confusing I ask for some opinions on my set up. My first concern is I/O, I feel like I won't have a problem, but have never set up a machine in such a configuration. My next concern is the mirroring between the two machines with three instances each running on them and about a total of thirty databases. There is a little I/O pressure in a few databases currently, but most due to bad clustered indexes which I will fix. Any opinions will help. If anyone needs holes filled in reply, and I will reply back.

    Thanks!

  • sherrerk (3/14/2011)


    By contract they have been asked to separate two of their clients onto separate hardware leaving me in a bit of a bind. My solution is to create multiple instances of the database on one server and partition off the data in separate RAID 10 volumes on an attached disk array.

    I snipped out this section because it's buried in your textwall.

    This is beyond a 'oh let me workaround what they're whining about' problem. This is a sincere auditing and contractual issue. They may either be competitors, or held by the same holding company and require by law a separation of all information and data.

    You need to review the physical contracts and speak with the clients before you decide to put these on the same machine, even as separate instances. The reason is your administrator NT logins will have the same security on the same box. This can be a critical issue. I know of one company that almost lost its two largest clients because of a FUBAR like this (and they will remain nameless, it wasn't done in malice).

    Don't just jump the fence on this and keep trucking. It's a critical issue and security wise may be very important. Get legal involved, they're the only ones who can cut through the red tape and contractese cleanly (well, cleanish...).


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  • I second what Craig says. There are numerous reasons why the business may desire/require a total separation.

    This is not a performance issue. In the past when faced with similar requirements, a separate instance on the same hardware (even though the disks are different), was not acceptable. Perhaps where you are at, it will be ok though.

    Not only are NT accounts shared, but also SQL logins having access to both databases may be a problem (sysadmin and other logins).

    Sounds like you need to have a full disclosure discussion of what they need and you can propose appropriate solutions to them. But you also need to disclose to them that most hardware is shared and some accounts will have access to both. Again, this may be ok since you personally will kinda need access to both databases.

    Jim

    Jim Murphy
    http://www.sqlwatchmen.com
    @SQLMurph

  • Thanks for the comments concerning the contracts. They are being reviewed and so far it seems that performance is most of the basis for separation. Legal issues may make make my hardware consideration moot, but I am still interested in comments about the configuration in case I am given the green light.

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