Michael Rothwell wrote:
> 
> What is the current scalability?

~10G max per server.

> 
> More info;
> Can a coda client also be a coda server? 

Yes, but then you must run both the server and the client software on
that machine and the files from the server will still be copied into the
cache. It becomes pretty slow.

Only a Coda client can access Coda files; you cannot go into the server
space directly.

The point I'm trying to make is that a Coda client has all the
availability characteristics you want.  Use ONE Coda server and for each
office a Coda client on which you run Samba. 

Clients have disconnected operation, so continue to work when the server
or net is down.  They also reintegrate changes to the server keeping a
single image consistent across all machines.

- Peter -


> We'd like to have a server pair at
> each location, so that up to three servers can fail before the system goes
> down. Here's a little diagram:
> 
> LOCATION ONE     LOCATION TWO
> 
> [W]  [S]         [S]  [W]
>   |--| |--=-=-=--| |--|
> [W]  [S]   wan   [S]  [W]
>   |                   |
> [W]                   [W]
>   |                   |
> [W]                   [W]
>   |                   |
> [W]                   [W]
> 
> The web servers would be Linux, Solaris and NT-based. NT clients would make
> use of SMD file service provided by SAMBA on the file servers. All four file
> servers would have to be kept in sync, so if a web server at location one
> opens a file and modifies it, none of the other webservers at either
> location would trample those changes. If a fileserver goes down and must be
> replaced, it will accept all files from a surviving file server as the
> current versions.
> 
> So, can four Linux servers running CODA be both clients and servers? Or
> would we need another set of machines todo the NFS and CIFS file service?
> 
> -M
> 
> > -----Original Message-----
> > From: Peter J. Braam [mailto:braam_at_cs.cmu.edu]
> > Sent: Wednesday, May 05, 1999 7:02 PM
> > To: codalist_at_TELEMANN.CODA.CS.CMU.EDU
> > Subject: Re: multiple CODA servers spread over a WAN
> >
> >
> > Michael,
> >
> > It might work.  You should play with Coda and see for yourself.  The
> > scalability at the moment might be too low for your needs.
> >
> > We very much encourage you to try this, because we like hearing about
> > problems and fixing them.
> >
> > In your situation, two Coda clients could act as the servers
> > to the two
> > sites - they would provide high availability if the WAN link
> > to the Coda
> > server went down.  Coda does not allow access to the server file space
> > except through a Coda client.
> >
> > - Peter -
> >
> >
> >
> > Michael Rothwell wrote:
> > >
> > > Hello. I just joined the CODA list, and I have a very
> > practical question.
> > >
> > > We have been attempting to get Veritas software running on
> > Solaris machines
> > > to properly replicate data between two servers that will
> > one day be in
> > > different states and connected via a WAN. Unfortunately,
> > the replication
> > > software attempts to open all inodes on the filesystem at
> > once and reliably
> > > causes a really bad kernel panic. Veritas has admitted that
> > it will not work
> > > in our situation and has bowed out. So we're looking for
> > other solutions.
> > > Storagetek is one possibility.
> > >
> > > The deal is, we will have mirrored file servers and
> > mirrored web servers in
> > > two different locations that must be kept in sync. If the
> > D.C. facility goes
> > > out, the Cary facility has to handle all the load until the
> > DC facility
> > > comes online (at which point the DC facility must be
> > synchronized). Also, if
> > > a CGI or other program on a webserver in D.C. updates a file, the
> > > counterpart Cary webserver must see the change. The
> > webservers should not be
> > > able to clobber each other's file changes. Veritas
> > accomplished this by
> > > locking files opened for writing.
> > >
> > > It looks like Coda may do what we need, from reading the
> > documentation. Does
> > > anyone have any insight? Or questions about our setup? I'd
> > be very happy to
> > > start using Linux and Coda rather than Solaris and X or
> > Network Applicance.
> > > I'd be happy to use anything that works.
> > >
> > > Thanks!
> > >
> > > Michael Rothwell
> > >   Director, Internet Application Development
> > >   InterLan Technologies
> > >   111 Corning Road #150
> > >   Cary, NC 27513
> > >   v: (919) 852-0690
> > >   f: (919) 852-0501
> > >   e: rothwell_at_interlan.net
> >