I have been seeing this a lot on my cluster as well. This typically happens for me if there are many maps (more than 5000) in a job.
Here is my cluster summary 342316 files and directories, 94294 blocks = 436610 total. Heap Size is 258.12 MB / 528 MB (48%) Configured Capacity : 26.57 TB DFS Used : 19.52 TB Non DFS Used : 606.9 GB DFS Remaining : 6.46 TB DFS Used% : 73.46 % DFS Remaining% : 24.31 % Live Nodes : 6 Dead Nodes : 0 Decommissioning Nodes : 0 Number of Under-Replicated Blocks : 57 I am trying to load a 1TB data from one table to another using Hive queries. It works well if I do it on small data sizes (around 500GB at a time). It is simple query insert into dest table (dynamic partition) select a, b, c from source table. Any idea how can I get this working. (Compressing the Map output to improve the performance) Have 8 Maps and 6 reduces per node. Thanks and Regards, Shantian ________________________________ From: Marc Sturlese <marc.sturl...@gmail.com> To: hadoop-u...@lucene.apache.org Sent: Mon, May 9, 2011 1:30:27 AM Subject: So many unexpected "Lost task tracker" errors making the job to be killed Options Hey there, I have a small cluster running on 0.20.2. Everything is fine but once in a while, when a job with a lot of map tasks is running I start getting the error: Lost task tracker: tracker_cluster1:localhost.localdomain/ 127.0.0.1:xxxxx Before getting the error, the task attempt has been running for 7h (and normally it takes 46sec to complete). Sometimes, another task attempt is launched in paralel, takes 50 sec. to complete and so the first one gets killed (the second one can even be launched in the same task tracker and work). But in the end, I get so many "Lost task tracker" so the job get killed. The job will end up with some of the task trackers blacklisted. If I kill the "zombie tasks", remove the jobtracker and tasktracer pid files, remove the userlogs and stop/start mapred, everything works fine again, but some days later, the error will happen again. Any idea why this happens? Could someway be related with having too many attempt folders in the userlogs (even that there is space left on device)? Thanks in advance. -- View this message in context: http://lucene.472066.n3.nabble.com/So-many-unexpected-Lost-task-tracker-errors-making-the-job-to-be-killed-Options-tp2917961p2917961.html Sent from the Hadoop lucene-users mailing list archive at Nabble.com.
