> I've never claimed that the ext2 is the best way to do RAID; I think MD
> is the way to do that. However, allowing ext2 to be able to support
> filesystems which span multiple block devices is a good thing to do, and
> a cleaner way of supporting multivolume support. Examples of
> filesystems which do this include the UDF filesystem used by DVD-ROM's,
> and Digital Unix's Advanced Filesystem.
What "feels wrong" about this to me is that all fs implementations are
then required to implement multiple device spanning, or they can't be
used on spanning partitions at all.
Conceptually it seems simpler to have the virtual layer which understands
how to span multiple partitions, but which looks like a block device from
the "user" view, thus allowing any filesystem type to be used upon it, be
that ext2, reiserfs, ufs or something even better that we haven't even
thought of yet. In this respect, MD seems like it's heading in the right
direction, though I believe it needs more support for mirroring and
striping (ie striped mirrors, or mirrors of stripes ?), better management
tools and full error recovery. I don't know if that's what LVM gets
you (if it's similar to Veritas Volume Manager, then I guess so), because
I haven't had the chance to look at it yet.
James.
--
"Yield to temptation -- | Consultancy: james@cloud9.co.uk
it may not pass your way again" | http://www.cloud9.co.uk/james
|
- Lazarus Long | James Fidell
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