While attending to o/374947, I found that running "./run_slave.py --no_save -y buildbot.tac" would state that the service had been started, but in fact it had failed because there was insufficient space on the storage device.

Ideally, the diskspace should be checked and an appropriate message printed to stdout/stderr if there is insufficient space.

[note, the error below from gclient doesn't appear to be relevant]

------------------------------
chrome-bot@build19-m2:(Linux 12.04):/b/build/slave$ ./run_slave.py --no_save -y buildbot.tac


internal.DEPS (ERROR)
----------------------------------------
[0:00:00] Started.
----------------------------------------
Error: Command 'git rev-parse --verify FETCH_HEAD' returned non-zero exit status 128 in /b/internal.DEPS
fatal: Needed a single revision

(./run_slave.py) `gclient sync` failed; proceeding anyway...
Using buildbot_slave_8_4 and twisted_10_2
Using slave name build19-m2
Using master host master2a.golo.chromium.org
Using master port 31508