On Tue, 2001-12-04 at 13:50, Roy Sigurd Karlsbakk wrote:
> >The XFS realtime subvolume is a separate dataspace in the filesystem, it
> >is only used for files marked as realtime after they are created. There
> >is nothing in the realtime subvolume except file data, where as in the
> >normal XFS data subvolume there is a mix of metadata and file data.
> >Space allocation in the realtime subvolume is managed by a different
> >allocator which gives out space in multiples of a pre-specified size,
> >the allocator uses a binary chop approach to space allocation which
> >is designed to avoid fragmentation at the expense of efficient use of
> >space - the allocator should also be faster.
> >
> >The end result is that streaming I/O should behave better on realtime
> >files and on regular files.
>
> ok. But XFS realtime subvolumes are, as I understand, not yet supported on
> Linux
> platform. Are there any plans of supporting it soon?
>
> How is a file placed or retrieved on the realtime subvolume? Is it flagged as
> it's
> been created, or does the realtime-part and the data-part come up as separate
> volumes
> with separate mount points?
See my previous email - the web page is wrong, and all the
details are in the mail message.
>
> >One feature which can be used on normal files which might help with
> >placement is preallocation of space. Take a look at the use of the
> >XFS_IOC_RESVSP64 ioctl in cmd/xfsprogs/mkfile/xfs_mkfile.c
>
> Is this available through /proc ?
??? No it is an ioctl interface to an xfs file, /proc has nothing
to do with it.
Steve
>
> roy
>
> --
> --
> Roy Sigurd Karlsbakk, MCSE, MCNE, CLS, LCA
>
> Computers are like air conditioners.
> They stop working when you open Windows.
--
Steve Lord voice: +1-651-683-3511
Principal Engineer, Filesystem Software email: lord@xxxxxxx
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