Coda File System

Re: Memory consumption

From: Phil Nelson <>
Date: Mon, 13 Dec 1999 09:04:47 -0800 (PST)
>I wanted to set up a Coda-Fileserver with 64MB RAM, 256MB swap and 8G
>fileserver space. This failed with an obscure error message and I
>tracked it down to having not enough memory.
>Now, with 3.3G fileserver space, the codasrv-process needs 180M virtual
>memory. Why does this is so high and how can I set up a fileserver with
>let's say 75G space?

Well, the server uses RVM to store metadata about the files being served.
All of RVM is memory mapped and thus take VM from your swap.  Using 4%
of the space served, you need about 330 Megs of RVM.  Thus, the 330 Megs
does not fit in the 256 MB swap.

There are recent changes to coda that allows the servers use private mapping
which should reduce the initial use of swap, but in the long term, the
server will still need all of RVM in swap.

I'm currently working on how get servers working with more capacity.  Our
current thoughts is that large servers, e.g. 75G, would need to be served
by multiple server processes.  For example, using 1G RVM should theoretically
allow you to serve 25G of files.  To serve 75G, you could run 3 servers
with 1G RVM.  That implies that you have more than 3G swap.  This hasn't been
done yet.  (I don't yet have the hardware available to try it, but I hope to
get enough to try 2 servers serving over 20G soon.)  

And I'm not sure anyone has run a server with 1G RVM.  So while we are working
toward this goal, we are not there yet.

Phil Nelson                    NetBSD:
e-mail:        Coda:    
Received on 1999-12-13 12:24:15