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He Xiaoqiao commented on HDFS-14186: ------------------------------------ Hi [~elgoiri], {quote}I'm guessing that the lifeline doesn't help because the DN is not registered at all?{quote} Yep, you are correct, lifeline do not help absolutely. Actually I have open the feature in my production cluster. {quote}I'm also curious about the numbers, 300M blocks takes 8 hours? We see around 30 minutes with 60M block.{quote} I found the case to different degrees with above 300M blocks. The worst case which takes more than 8 hours I met: more than 15K nodes with more than 500M blocks. Generally, I think number of slave nodes and block numbers both can impact the startup times under the same fsimage+editlogs. blocks number is more affected factor of course. 30min can finish to restart with 60M blocks, I see the same result as [~elgoiri] mentioned. Actually, with 100M blocks or less we can control startup time within ~40min. It appears with more large-scale. more comments are welcome. > blockreport storm slow down namenode restart seriously in large cluster > ----------------------------------------------------------------------- > > Key: HDFS-14186 > URL: https://issues.apache.org/jira/browse/HDFS-14186 > Project: Hadoop HDFS > Issue Type: Improvement > Components: namenode > Reporter: He Xiaoqiao > Assignee: He Xiaoqiao > Priority: Major > Attachments: HDFS-14186.001.patch > > > In the current implementation, the datanode sends blockreport immediately > after register to namenode successfully when restart, and the blockreport > storm will make namenode high load to process them. One result is some > received RPC have to skip because queue time is timeout. If some datanodes' > heartbeat RPC are continually skipped for long times (default is > heartbeatExpireInterval=630s) it will be set DEAD, then datanode has to > re-register and send blockreport again, aggravate blockreport storm and trap > in a vicious circle, and slow down (more than one hour and even more) > namenode startup seriously in a large (several thousands of datanodes) and > busy cluster especially. Although there are many work to optimize namenode > startup, the issue still exists. > I propose to postpone dead datanode check when namenode have finished startup. > Any comments and suggestions are welcome. -- This message was sent by Atlassian JIRA (v7.6.3#76005) --------------------------------------------------------------------- To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org