Thanks for the replies. I have turned off swap on all the machines to prevent any swap problems. I was pounding my hard drives quite hard. I had a simulated 60 clients loading data as fast as I could into hbase with a map reduce export job going at the same time. Would that scenario explain some of the errors I was seeing?

Over the weekend under more of a normal load I haven't not any exception except for about 6 of these: 2010-06-05 03:46:41,229 ERROR datanode.DataNode (DataXceiver.java:run(131)) - DatanodeRegistration(192.168.0.98:50010, storageID=DS-1806250311-192.168.0.98-50010-1274208294562, infoPort=50075, ipcPort=50020):DataXceiver org.apache.hadoop.hdfs.server.datanode.BlockAlreadyExistsException: Block blk_-1677111232590888964_4471547 is valid, and cannot be written to. at org.apache.hadoop.hdfs.server.datanode.FSDataset.writeToBlock(FSDataset.java:999)

The reason the config shows 4096 is because I increased the xceiver account after the first email message in this thread.

~Jeff

Allen Wittenauer wrote:
On Jun 4, 2010, at 12:03 PM, Todd Lipcon wrote:

Hi Jeff,

That seems like a reasonable config, but the error message you pasted indicated 
xceivers was set to 2048 instead of 4096.

Also, in my experience SocketTimeoutExceptions are usually due to swapping. 
Verify that your machines aren't swapping when you're under load.

Or doing any other heavy disk IO.


--
Jeff Whiting
Qualtrics Senior Software Engineer
je...@qualtrics.com

Reply via email to