Re: Bigfile tablespaces on OS filesystems?

Read write performance would be horrible if you don't use a concurrent IO-capable and -enabled filesystem.

I guess you're on JFS2 then? JFS2 is rebrandede VxFS, which doesn't have concurrent IO unless you use QuickIO (which you want to avoid) or Oracle ODM library, which should be ok.

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Tanel Poder
http://blog.tanelpoder.com

On Tue, Sep 22, 2009 at 1:44 AM, Lou Avrami <avramil_at_concentric.net> wrote:

Hello all,

I have an INTERESTING scenario that I would like to run by you folks.

I have been assigned the task of migrating an existing data warehouse of approximately 2 TB to a new server running 11gR1.  After much discussion ... the UNIX/SAN team will not OK using ASM, so I am stuck with creating tablespaces on OS filesystems.

Originally, I wanted to use bigfile tablespaces for the larger tablespaces, in conjunction with ASM.  Now that ASM is out the window (at least for the moment - maybe we will be allowed to migrate to it someday), does it still make sense to use bigfile tablespaces?

The OS that the new data warehouse will be on is HP-UX 11.23, so I believe that means no asynch I/O at the filesystem level.

What would the read/write performance be like for something like a 500 GB bigfile tablespace on a UN IX OS filesystem?   My initial impression is that concurrent reads and writes would have horrible performance, because UNIX would "force" the entire 500 GB file to be accessed for each read/write operation.

From a read/write performance perspective, would it be better to use smallfile tablespaces with multiple uniform datafiles?

Any helpful information would be much appreciate down here in the rabbit hole.  :-)

Thanks,
Lou Avrami


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