logbufs default value

logbufs default value

[Michael Weissenbacher]

Hi List!
>From linux-2.6.39/Documentation/filesystems/xfs.txt:
  logbufs=value
        Set the number of in-memory log buffers.  Valid numbers range
        from 2-8 inclusive.
        The default value is 8 buffers for filesystems with a
        blocksize of 64KiB, 4 buffers for filesystems with a blocksize
        of 32KiB, 3 buffers for filesystems with a blocksize of 16KiB
        and 2 buffers for all other configurations.  Increasing the
        number of buffers may increase performance on some workloads
        at the cost of the memory used for the additional log buffers
        and their associated control structures.

Is this still valid? I thought that newer kernels would always use 8 as
default?

tia,
Michael

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Re: logbufs default value

[Dave Chinner]

On Sat, May 28, 2011 at 09:45:16AM +0200, Michael Weissenbacher wrote:
> Hi List!
> From linux-2.6.39/Documentation/filesystems/xfs.txt:
>   logbufs=value
>         Set the number of in-memory log buffers.  Valid numbers range
>         from 2-8 inclusive.
>         The default value is 8 buffers for filesystems with a
>         blocksize of 64KiB, 4 buffers for filesystems with a blocksize
>         of 32KiB, 3 buffers for filesystems with a blocksize of 16KiB
>         and 2 buffers for all other configurations.  Increasing the
>         number of buffers may increase performance on some workloads
>         at the cost of the memory used for the additional log buffers
>         and their associated control structures.
> 
> Is this still valid? I thought that newer kernels would always use 8 as
> default?

No, it's not. Patches to fix the documentation are welcome.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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