Coda File System

bandwidth measure and disconnections

From: Juan Carlos Schroeder <>
Date: Wed, 23 Jun 2004 00:07:46 -0300
I have some doubts about disconnections and the measure of bandwidth that
venus does.

My client and server are connected through a 10Mbps (local) connection.
My server is running in a Linux VMware virtual machine inside Windows, but
it is connected to the network as any other computer. The client is a normal
Linux client connected to the LAN.

1) My venus client does not really measure quite well my connection
bandwidth.Having the full bandwidth dedicated to this, it rarely measures
more than 30000 bytes per second (I think that's the "unit" used to show the
bandwidth measure that venus uses).
It also oscilates too much, ranging from a few cents (200-300) of bytes to a
two or three cents of thousands (100000-200000).
I'm reading this measures with both "codacon" executable and reading
"venus.log" (previously configuring the debug output with "vutil d 100").
I've also reduced bandwidth using a Windows software, and it also works
quite bad.

2) I've had troubles to reconnect. Using "cfs strong" and then "cfs wr" it
sometimes reconnects, but other times not. Also, some times reconnected
after a minute or two, or even more.
With these delays, I don't really know which command was necessary to

What should I do to be "connected"? What would be the sequence of commands?
What would be the advantages of being "connected" over being
"write-disconnected" with "write-back" enabled ? Consistency and

3) What is necessary to enable writeback mode? At first I couldn't enable
writeback mode ("cfs wbstart"), in spite of having no "entries pending" in
the CML. I tried to enable writeback on the volumes on the server, and each
time it returned me an error. I don't think writeback was enabled before
that because I hadn't enabled this since the volume was created.
After some time, I could, but I know why.

What is necessary to enable write-back mode?
Is it possible to be "connected" and in "write-back" mode?

4) How would Coda work with a lower "threshold" to decide to be "connected"
or "write-disconnected"? I plan to use low bandwidth internet links (about
I don't know Coda's code, but, would be hard to change this part?
If anyone knows some utility to manage the bandwidth and latency, I'd also
be very grateful.

Thanks a lot,

Juan Carlos
Received on 2004-06-22 23:21:16