Coda File System

write failure issues

From: <shivers_at_cc.gatech.edu>
Date: Fri, 14 May 2004 12:18:09 -0400
Three machines:
  - Server (debian)
  - ClientW, sessile system on net via cable modem. (RedHat)
    Has a large media filesystem (i.e., big files)
  - ClientR, a notebook (RedHat)

ClientW & ClientR are both running coda clients. Server is the coda server.

On ClientW, I am slowly copying a set of large files into
    /coda/Server/shivers
By "slowly," I mean that I copy a file, then sleep 8 min, then copy another.
This gives the client plenty of time to upload the bits to Server. (I have
a 100Mb venus cache on ClientW, which is larger than the total write size
(~ 46Mb), so there *shouldn't* be an issue, but see below.)

On ClientR, I can see the files I am copying on ClientW as they are uploaded
to Server with
    ls -l /coda/Server/shivers
Cool!

Things go wrong when I just say on ClientW
    cp <12-big-files> /coda/Server/shivers/.
The system writes about three files, then things get screwy & disconnected.
What happens, I *think*, is that the write goes in two stages: it's written
into the venus cache quickly, then dribbles out over my cable modem slowly.
When this bottleneck causes enough reintegration data to build up, blammo.
The lossage is as I described in my last message: cfs lv shows the system
in some kind of disconnected state, and cfs wr won't make it reconnect.

So the message seems to be that if I don't press the system hard, it works.
Under pressure, it falls over. For me, that's progress. Now I want to
understand the current hosage. Can anyone help?
    -Olin 
Received on 2004-05-14 12:49:14