Re: (reiserfs) Re: Implementing Meta File information in Linux (and a note at the
Richard Gooch (rgooch@atnf.csiro.au)
Fri, 4 Sep 1998 17:43:26 +1000
H. Peter Anvin writes:
> Followup to: <199809031247.WAA16479@vindaloo.atnf.CSIRO.AU>
> By author: Richard Gooch <rgooch@atnf.csiro.au>
> In newsgroup: linux.dev.kernel
> >=20
> > > > Of course, if you have large metadata, then you're better off makin=
> g
> > > > each stream as a file in a directory and letting the FS do the work.
> > > > The FS code already has one bunch of code to implement growing stre=
> ams
> > > > (files), I think we'd want to leverage that instead of implementing
> > > > yet another level of what is effectively file/directory management
> > > > inside the FS.
> >=20
> > To clarify: I see two situations. The first is where you have a small
> > number of secondary streams of small size which don't grow much. Here
> > a single file can suffice.
> > The second case is where these assumptions break down, and in that
> > case I think each stream belongs in a file. A userspace API is written
> > to allow you to deal with the dataset as a single object. For
> > consistency, even where the above assumptions hold, it's probably
> > better to use one file per stream.
> > I see directories being excellent placeholders for grouping
> > metadata. With reiserFS, this userspace implementation will be very
> > fast, so it's the logical way to go, IMO.
> >=20
>
> For the small data objects (i.e. "resources"), it seems that using a
> standard database library like gdbm or db is appropriate.
Except (see my earlier post) that keeping things in a separate
catalogue also has it's problems. It makes it impossible to use
standard tools to move/backup a file with all it's metadata. A
sysadmin also has to know the specialised tools to deal with the
metadata. That's why I think the data and metadata should be kept in
the one place: either all in one file or using a directory.
Anyway, I see all of this as a userspace problem.
Regards,
Richard....
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