[plug] File sync; users over WAN with disparate fileservers

[Bernd Felsche]

William Kenworthy <billk at iinet.net.au> writes:

>On Sat, 2004-11-13 at 15:50 +0800, Bernd Felsche wrote: 
>> I'm about to start doing something a little "unusual".

>> Users logged in over a WAN can create files on a server using an ERP
>> application.

>Something like a webdav share may be more suitable so you can stay with
>a central server - simplifies things a lot.

Webdav? Some of the reports contain sensitive data (privacy act)
that must be protected from the view of others on the VPN. If I
understand the concept of Webdav correctly, it's for multiple users
sharing the same files (for collaborative authoring, etc), not for
one user having transparent mirroring of file changes between
systems. Webdav must sustain user permissions; and the wwwrun user
permissions of the apache server don't have access to the user's
files. It doesn't seem like a good fit.

>Otherwise coda, or afs ?  Manual syncing using unison/rsync is really
>more for offline syncing and not for live systems.

Too slow for central server. Throughput over WAN is under 10
kilobytes/second; often less as it's a VPN over ADSL connecting to 6
remote sites. Files can be tens of megabytes of rain-forest
deveastating reports. So they compete for a single outbound
connection if constant access is required. Also, traffic is volume
charged so repeated access off a central server is simply going to
escalate operating overhead costs.

I've now looked at Coda and the official site
http://www.coda.cs.cmu.edu/ has no changes since 2000. 
I hope that there's a current site and further development because
according to the official documentation, Coda is not ready for
production use.

There are kernel modules available in the systems as deployed but
documentation is UTSL. I've got to read a lot of possibly-obsolete
documentation before I can determine if it'll allow me to determine
which parts of a failesystem get "mirrored" to each server without
extraneously mirroring content not required at remote sites.
It appears that Intermezzo (intersync) is the successor to Coda
anyway, being an effort of Peter J. Braam.

The situation is similar for OpenAFS... though it does appear to
under current development with a bit more documentation available.

>By the way, you seem to have posted from a newsgroup server which
>has a stuffed up reply to - evolution is trying to make sense of
>the address

News servers don't have "reply-to". Reply-To is an email paradigm.
Posting to a news server doesn't require a Reply-To header. If it's
tehre, it'll be carried through just like X-Useless-Header. It's not
required for news transport or presentation. Any Reply-To header
added by the PLUG mail to news gateway is way beyoond my control.

>and fails - in fact I have had to cut and paste it into a normal email
>message to send it!

That's an Evolution issue. Failing to make the distinction between
email and news is a common problem.

[I have to get some sleep now]
-- 
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