SQL Server Performance

System DBs and named instances on one LUN

Discussion in 'SQL Server 2005 Clustering' started by cabledguy2006, Mar 1, 2009.

  1. cabledguy2006 New Member

    Hi All

    I've been tasked with creating an SQL cluster which a number of systems will use for database services. What they've given me to work with is a bit different to how I'd lay it out.

    What I've been given is two TB LUNs on a mid-level FC SAN. So the SQL binaries will go on local disk and the system databases and a number of databases in named instances will be all sharing one big LUN/(drive in windows).
    One issue I could see is I will run out of I/O long before using up the 2 TB and so end up wasting a lot of space.
    The LUNs are dedicated Database tier so won't be sharing with other uses but it's a consolidated service so there will be a lot of different databases with different load profiles.

    I assume we can have multiple named instances per node as long as we have multiple resource groups.

    But actually is this going to work at all? Won't each instance be dependent on a disk resource and so have to be different disk.
  2. Elisabeth Redei New Member

    If I understood your concern correctly, you have come to the right conclusion. A resource (such as a disk drive) cannot be shared between two resource groups so you will need at least one unique (shared) drive for each SQL Server virtual server.
    And quite possibly you will end up wasting space unless your database(s) end up consuming the TB.

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