Xen users - Sep 2005 - xm save question

Hello,

We would like to centrally manage the saved states of our domU''s, which
could be spread among various physical machines and unfortunately cannot 
use NFS.  So one idea we had was to create a named pipe so one could 
save into this pipe and we would have a process reading the pipe which 
could handle moving the save file to a central repository.  As an 
experiment I created a simple program to create the pipe and it seems to 
work okay if I cat a file into the pipe.  However if I use the fifo as 
an argument to the "xm save" command, the save completes quickly, but
my
program does not see any data come across until it closes the pipe.  In 
addition, I am unable to restore the domU from the resulting file.

I''m assuming the issue is within my code, but figured I run the
question
in case there is an obvious reason why this would not work, or if there 
is a better solution.

Thanks in advance,

Pat

-- 
Patrick O''Rourke
porourke@egenera.com

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To follow up... it seems the issue is due to xend not closing the save 
file (see attached).  An ls of /proc/<xend-pid>/fd shows about 20 open 
files with a single domU.  I then did a save, restore and save of the 
same domU (to files "/root/sxps/save-a" and
"/root/sxps/save-b"
respectively) and it seems that xend is not closing the file - either 
after a save or a restore.

This is on xen-unstable bits, built from the source tarball dated 9/25/05.

Pat

p.s. FWIW, I am able to do the save to a named pipe.  Once I updated my 
system w/ the above tarball, I could restore the domain.

-- 
Patrick O''Rourke
porourke@egenera.com


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