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Wei-Chiu Chuang commented on HDFS-14084: ---------------------------------------- bq. I'm not sure on the best way to get the information out... logging (trace leve?) might be too verbose but I don't see many more ways. IMO logging latency number at trace level (for each op?) doesn't work too well. For most part I am interested in the distribution of latency number. For example, 50%-tile,90%-tile,99%-tile, of OP_DELETE, over some period of time, say the past 30 seconds, 5 minutes. We already have something similar at RPC server level (via config key dfs.metrics.percentiles.intervals), just that we don't have that in the client side. > Need for more stats in DFSClient > -------------------------------- > > Key: HDFS-14084 > URL: https://issues.apache.org/jira/browse/HDFS-14084 > Project: Hadoop HDFS > Issue Type: Improvement > Affects Versions: 3.0.0 > Reporter: Pranay Singh > Assignee: Pranay Singh > Priority: Minor > Attachments: HDFS-14084.001.patch > > > The usage of HDFS has changed from being used as a map-reduce filesystem, now > it's becoming more of like a general purpose filesystem. In most of the cases > there are issues with the Namenode so we have metrics to know the workload or > stress on Namenode. > However, there is a need to have more statistics collected for different > operations/RPCs in DFSClient to know which RPC operations are taking longer > time or to know what is the frequency of the operation.These statistics can > be exposed to the users of DFS Client and they can periodically log or do > some sort of flow control if the response is slow. This will also help to > isolate HDFS issue in a mixed environment where on a node say we have Spark, > HBase and Impala running together. We can check the throughput of different > operation across client and isolate the problem caused because of noisy > neighbor or network congestion or shared JVM. > We have dealt with several problems from the field for which there is no > conclusive evidence as to what caused the problem. If we had metrics or stats > in DFSClient we would be better equipped to solve such complex problems. > List of jiras for reference: > ------------------------- > HADOOP-15538 HADOOP-15530 ( client side deadlock) -- 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