Offspring should warn about low disk space on the build slaves, and report in a better way about it.
Only one of our builds resulted in something indicative of the problem:
...
Setting up live-build (3.0~a34-1-1linaro10~maverick5) ...
P: Copying project configuration directory into work directory for build... done.
P: Generating buildstamp... done.
P: Adding buildstamp to binary image... done.
P: Generating distribution channel descriptor... done.
I: Fault handler set to DISALLOW errors
P: Loading required configfile '/var/tmp/offspring/linaro-o-server/config/bootstrap'... done.
P: Loading required configfile '/var/tmp/offspring/linaro-o-server/config/chroot'... done.
P: Loading required configfile '/var/tmp/offspring/linaro-o-server/config/binary'... done.
P: Loading required configfile '/var/tmp/offspring/linaro-o-server/config/source'... done.
I: Saving copy of build setup to build results directory.
bzr: ERROR: [Errno 28] No space left on device: '/srv/builds/linaro-o-server/20120315/0/config/'
E: A fatal error has ocurred. Shutting down.
where the rest of them simply finished with ERROR as the build name and had nothing in the log files other than during dpkg configuration step. The rest didn't even get a chance to start writing their log files.
(All of our buildds use a NFS mount under /srv/builds which caused mass failures for us: this is where log files get written as well)
Will look into this on our end.