For OOM, memory related option `bsp.child.java.opts' can be added to hama-site.xml for increasing memory size; or consider reducing memory footprint.
Based on the setting at hand, max tasks, i.e. peer, can be configured via `bsp.tasks.maximum' with default set to 3. IIRC, peer process is something like child process in original mapreduce where task tracker will fork a child processing algorithm, mainly for fault isolation. On 14 January 2014 17:21, 步青云 <[email protected]> wrote: > Hello, > I've got some problem about Hama program on large dataset.My hama > cluster has 3 computers.One is bspmaster,other 2 computers is > groomserver.When the graph has one million nodes,the pagerank running will > stop at "Current Superstep Number:0".The error information is as follows: > > > attempt_201401141543_0015_000000_0: 14/01/14 17:07:55 ERROR bsp.BSPTask: > Shutting down ping service. > attempt_201401141543_0015_000000_0: 14/01/14 17:07:55 FATAL bsp.GroomServer: > Error running child > attempt_201401141543_0015_000000_0: java.lang.OutOfMemoryError: Java heap > space > attempt_201401141543_0015_000000_0: at > java.util.Arrays.copyOf(Arrays.java:2271) > attempt_201401141543_0015_000000_0: at > java.io.ByteArrayOutputStream.grow(ByteArrayOutputStream.java:113) > attempt_201401141543_0015_000000_0: at > java.io.ByteArrayOutputStream.ensureCapacity(ByteArrayOutputStream.java:93) > attempt_201401141543_0015_000000_0: at > java.io.ByteArrayOutputStream.write(ByteArrayOutputStream.java:140) > attempt_201401141543_0015_000000_0: at > java.io.DataOutputStream.write(DataOutputStream.java:107) > Should I add the number of computers of cluster to solve this > problem?Any other solution? > > And I also want to know how many peers a groomserver can run?Is a peer > correspond to a node in graph mode?If so,I have one million of nodes in a > graph and if one groomserver run 500 peers,so I need 2000 groomservers > correspond to 2000 computers.In my opinion,it's not convenient. > By the way,what's a appropriate value of "bsp.tasks.maxinum" in Hama > conf ?Is the number of computer of cluster a appropriate value? > Thanks! > Best wishes.
