Excerpts from mail: 18-Nov-94 Re: news server in AFS? James R.
[EMAIL PROTECTED] (769+0)
> Besides, unless you can find a way to circumvent the "callback problem"
> (and address other issues, like subdividing hierarchies across AFS
> volumes), moving your news spool into AFS space will almost certainly be
a *lose*, not win.
Putting a netnews feed into AFS slows service somewhat, but gives the
advantages of nearly unlimited disk storage, dynamic quota management,
nightly backup and enhanced fault tolerance.
To circumvent the callback problem, we use a very large local cache on
the news server (-files 64000). This lets us keep the latest couple of
days worth of articles cached locally, ready for quick retrieval. (Most
regular news customers are primarily interested in reading fresh
articles, which are usually still in the local cache; they therefore
don't experience long delays in the retrieval process due to repeated
AFS server callbacks).
Subdividing news hierarchies across AFS volumes works as follows (using
C-NEWS):
- /usr/spool/news is a symbolic link into AFS
- Each major newsgroup within /usr/spool/news is a separate AFS volume.
- /usr/spool/news/in.coming is a symbolic link back to the local disk.
This lets incoming news spool into a local disk directory, unimpeded by
AFS.
- When "relaynews" unspools the incoming newsbatch into the respective
netnews hierarchies, it does so by writing directly into AFS. The
result is that fresh news articles are cached locally on the news server
(where they will remain available for quick access for a couple of
days), and each article is written as well to an AFS w/r volume for long
term storage and nighlty backup.
By placing the incoming news directory on local disk, but news
hierarchies in AFS, we circumvent synchronization and locking problems
that could result if remote newsfeeds spooled directly into AFS. (When
AFS is unavailable, incoming news accumulates in a local disk directory
for later processing).
Spooling into restricted AFS space is accomplished by running nntpd with
"netnews" (a special AFS UID) tokens, perpetually refreshed via
"reauth". Remote users wishing to read news via nntp inherit "netnews"
tokens when they contact the news server, allowing them to read news
from otherwise restricted AFS space.
Heavily used news servers (ie, lots of concurrent users) will eventually
become bogged down by keeping news in AFS, but for smaller-scale
applications, this setup can be a win-win situation!
Note: B-NEWS doen't allow the spooling area to cross file partitions,
so AFS volumes can't be used to span a B-NEWS directory tree.
