you should use the web UI --each mapper / reducer can be inspected and there is no need to ssh in.
Miles 2008/8/7 Karl Anderson <[EMAIL PROTECTED]> > > On 28-Jul-08, at 6:33 PM, charles du wrote: > > Hi: >> >> I tried to run one of my map/reduce jobs on a cluster (hadoop 0.17.0). >> I used 10 reducers. 9 of them returns quickly ( in a few seconds), but >> one has been running for several hours, and still no sign of >> completion. Do you know how I can debug it or find out what is going >> on with this reducer? >> > > You can log, and set the status message. If you're using streaming, I > think you're limited to writing to stderr. The only way I've found to read > the logs on a distributed run is by sshing to the actual task box and > looking at the log directory. I've almost gotten frustrated enough to have > my tasks send email, but not quite. > > Debugging is easier on a single pseudodistributed box because all the logs > and stderr is right there, so try that if you can. > -- The University of Edinburgh is a charitable body, registered in Scotland, with registration number SC005336.
