On Mon, Mar 10, 2008 at 5:07 PM, David Chinner <dgc@xxxxxxx> wrote:
> On Fri, Mar 07, 2008 at 03:39:05PM +1100, Niv Sardi wrote:
> > Incorporated Eric's changes, last call does it look good to everyone
>
> > @@ -387,17 +399,13 @@ With some combinations of filesystem block size,
> inode size,
> > and directory block size, the minimum log size is larger than 512 blocks.
> > .TP
> > .BI version= value
> > -This specifies the version of the log. The
> > -.I value
> > -is either 1 or 2. Specifying
> > -.B version=2
> > -enables the
> > -.B sunit
> > -suboption, and allows the logbsize to be increased beyond 32K.
> > -Version 2 logs are automatically selected if a log stripe unit
> > -is specified. See
> > -.BR sunit " and " su
> > -suboptions, below.
> > +This specifies the version of the log. The current default is 2,
> > +which allows for larger log buffer sizes, as well as supporting
> > +stripe-aligned log writes (see the sunit and su options, below).
> > +.IP
> > +The previous version 1, which is limited to 32k log buffers and does
> > +not support stripe-aligned writes, is kept for backwards compatibility
> > +with very old 2.4 kernels.
> I don't like this change. You're removing specific references to the
> commands needed to set sunit, or how to set the version number, and what
> the default behaviour on stripe aligned filesystems are.
Right that should be added back.
> Secondly, version one logs are not being kept around for backwards
> compatibility reasons. It's a valid, supported configuration, and in
> some cases performs better than version 2 logs....
Can you be more specific ? the man page should document when this is
better supported and I believe you're the one that has the best
knowledge about that.
> Realistically, I see no need for changing this text except to add that
> the default is version 2.
The change was motivated by Eric's comments on OSS that it is not
clear why one should pick log v1 or v2, and I believe he is right.
Cheers,
--
Niv Sardi
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