[OpenAFS] cache managers on openAFS clients NOT caching

Kristian kristian@hitech-sanita.it
Tue, 05 Oct 2004 18:18:04 +0200

Il gio, 2004-09-30 alle 18:16, Jim Rees ha scritto:
> Your CM should not be re-fetching the file if it hasn't changed.  It doesn't
> matter whether it has a callback or not.
> You forgot to answer Derek's question so I'll repeat it here.  Are you sure
> you're seeing data re-fetch and not just volume/stat information?  How do
> you know?

	I have been away for a couple of days... sorry for getting back to you
all so late.

	The way I knew that the CM was re-fetching the data was by looking at
timing information I collected by "cat-ing" a 200MB file to /dev/null,
and by looking at network activity on my gkrellm diagram.
Stat/volume information should not generate anything close to the
traffic generated by the transferring of a 200MB file... that's how I
know. In fact IT WAS re-fetching the data (Derrick... I also tried your
"tcpdump -s 1500 etc etc"... there's a lot of difference in the number
of fetch-data lines between a run with an empty cache and a cached
run... in the second case I noticed a few lines with fetch-status which
probably correspond to stat/volume queries from the client to the

	In any case, after spending a couple of days verifying the behaviour of
the CM, I found out that, apparently, if I shutdown the CM right after
the execution of firefox, the CM simply ignores the locally stored copy
upon restart. On the other hand, if I run the binary and leave the CM
running for some time (not sure how long.. I left it for about an hour)
before restarting it, the CM works as I expected and retrieves the file
from the local cache. Why?

Kristian <kristian@hitech-sanita.it>