>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
platform. Are there any plans of supporting it soon?
How is a file placed or retrieved on the realtime subvolume? Is it flagged as
been created, or does the realtime-part and the data-part come up as separate
with separate mount points?
>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 ?
Roy Sigurd Karlsbakk, MCSE, MCNE, CLS, LCA
Computers are like air conditioners.
They stop working when you open Windows.