RE: Filesystem Block Size ? 1K or 4K or 8K ?

From: Powell, Mark D <>
Date: Tue, 14 Oct 2008 10:15:10 -0400
Message-ID: <>

If the Oracle block size is 8K I see no valid reason why I would want an OS block size less than 8K. By having an 8K OS and Oracle block size one Oracle IO will equal one OS IO.  

  • Mark D Powell -- Phone (313) 592-5148

[] On Behalf Of Zhu,Chao

	Sent: Tuesday, October 14, 2008 9:32 AM
	Subject: Re: Filesystem Block Size ? 1K or 4K or 8K ?
	Q1: I don't have performance test result about HP vxfs. But
vxfs_at_solaris using directio does not seems to make much difference per my past experience. And whether direct IO helps/how much it helps really depends on application profile. Same with Raw Devices. (more heavy write, more saving on CPU and better throughput.)
	Q2: see metalink note 139272.1
	I don't see any benefit of using 1k/4k filesystem pagesize for a
8k db_block_size database. Won't consider that at all.                  

        On Tue, Oct 14, 2008 at 7:49 PM, VIVEK_SHARMA <> wrote:                                            

                From: []                                  

                If direct io is being used, the difference maybe less.

                Qs 1 -> What do you mean by "the difference maybe less."?                 

		Anyway I don't see any benefit using 1k/4k blocksize.
		If you want best throughput, go with raw volumes.

		Have done all tuning on hp kaio setup to maximize os

                Qs 2 -> Could you share some "tuning on hp kaio setup" please?                                   


                HP who is partnering the Benchmark states - since Filesystems are being Mounted with Direct I/O therefore 1K F.S. block size is preferred to 8K.                                   

                From: []

                Of course set to 8k                 

                We are in the process of Setting up DB Server for an OLTP Banking Application Benchchmark.                  

                HP-UX B.11.31

                system device block size(think this is the O.S. block size) = 1K

                Base page size = 4K.

                DB_block_size = 8K                  

                Should the Filesystem (VXFS) Block Size be set to 1K, 4K or 8K? ... Personally I think it should be 4 K (i.e. Equal to the Page-size)                  

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	Zhu Chao

Received on Tue Oct 14 2008 - 09:15:10 CDT

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