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Flume >> mail # user >> Log Events get Lost - flume 1.3

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RE: Log Events get Lost - flume 1.3
Hi Brock,
Thanks for assisting.

Actually we have an interceptor implementation through which we are generating our row key for hbase (hbase is sink). If we have larger batch size then the chances are that the timestamp is getting repeated in rowkey which would overwrite the rows in hbase.

Could you please guide me if we do have any work around so that I can have larger batchsize as well as the row key is not repeated. I am taking the count till nano timestamp.


  public Event intercept(Event event) {
//      eventCounter++;
    //env, logType, appId, logPath and logFileName
    Map<String, String> headers = event.getHeaders();
    long now = System.currentTimeMillis();
    String nowNano = Long.toString(System.nanoTime());
    //nowNano = nowNano.substring(nowNano.length()-5);

    headers.put(TIMESTAMP, Long.toString(now));
    headers.put(HOST_NAME, hostName);
    headers.put(ENV, env);
    headers.put(LOG_TYPE, logType);
    headers.put(APP_ID, appId);
    headers.put(LOG_FILE_PATH, logFilePath);
    headers.put(LOG_FILE_NAME, logFileName);
    headers.put(TIME_STAMP_NANO, nowNano);

    return event;

  public List<Event> intercept(List<Event> events) {
    for (Event event : events) {
    return events;
From: Brock Noland [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, April 16, 2013 10:39 AM
Subject: Re: Log Events get Lost - flume 1.3


There are two issues with your configuration:

1) batch size of 1 with file channel is anti-pattern. This will result in extremely poor performance because the file channel will have to do an fsync() (expensive disk operation required to ensure no data loss) for each event. Your batch size should probably be in the hundreds or thousands.

2) tail -F *will* lose data. There is a writeup on this in documentation. If you care about your data, you will want to use Spooling Directory Source.

Issue #2 is being worsened by issue #1. Since you have such a low batch size, throughput of the file channel is extremely low. As tail -F results in no feedback to the tail process, more data than is being lost than would otherwise be the case due to the low channel throughput.

On Tue, Apr 16, 2013 at 3:16 AM, Kumar, Deepak8 <[EMAIL PROTECTED]<mailto:[EMAIL PROTECTED]>> wrote:


I have 10 flume agents configured at a single machine. A single log file has frequency of 500 log events/sec. Hence in 10 log files the logs are getting generated as 5000 log events per second (5000/sec).

If my channel capacity is 1 million,  more than 70% of log events is lost! If I increase the channel capacity to 50 millions, then flume agent takes more than 24 hours to transfer the log events from source to sink.

The size of dataDir (agent.channels.fileChannel.dataDirs = /var/log/flume-ng/file-channel/data) is almost 2G all the time.

Could you please guide me the optimum configuration so that I don't miss any of log events & the transfer is also good enough. My flume-conf.properties has following contents:

agent.channels = fileChannel

agent.sinks = avroSink

# Each sink's type must be defined

agent.sinks.avroSink.type = avro

agent.sinks.avroSink.hostname = spnnq01.nam.nsroot.net<http://spnnq01.nam.nsroot.net>

agent.sinks.avroSink.port = 1442

agent.sinks.avroSink.batchSize = 1000

#Specify the channel the sink should use

agent.sinks.avroSink.channel = fileChannel

# Each channel's type is defined.

agent.channels.fileChannel.type = file

agent.channels.fileChannel.checkpointDir = /var/log/flume-ng/file-channel/checkpoint

agent.channels.fileChannel.dataDirs = /var/log/flume-ng/file-channel/data

agent.channels.fileChannel.transactionCapacity = 1000

agent.channels.fileChannel.checkpointInterval = 30000

agent.channels.fileChannel.maxFileSize = 2146435071<tel:2146435071>

agent.channels.fileChannel.minimumRequiredSpace = 524288000

agent.channels.fileChannel.keep-alive = 5

agent.channels.fileChannel.write-timeout = 10

agent.channels.fileChannel.checkpoint-timeout = 600

agent.channels.fileChannel.capacity = 50000000

agent.sources.s2.batchSize = 1

agent.sources.s2.channels = fileChannel

agent.sources.s2.command = tail -F /var/log/creditcard/AggKeyListener.2.2013-01-19

agent.sources.s2.interceptors = logIntercept

agent.sources.s2.interceptors.logIntercept.appId = 153299

agent.sources.s2.interceptors.logIntercept.env = SP

agent.sources.s2.interceptors.logIntercept.hostName = vm-e61b-fe34.nam.nsroot.net<http://vm-e61b-fe34.nam.nsroot.net>

agent.sources.s2.interceptors.logIntercept.logFileName = AggKeyListener.2.2013-01-19

agent.sources.s2.interceptors.logIntercept.logFilePath = /var/log/creditcard/

agent.sources.s2.interceptors.logIntercept.logType = creditcard log

agent.sources.s2.interceptors.logIntercept.type = com.citi.sponge.flume.agent.source.LogInterceptor$Builder

agent.sources.s2.type = exec

agent.sources.s0.batchSize = 1

agent.sources.s0.channels = fileChannel

agent.sources.s0.command = tail -F /var/log/creditcard/AggKeyListener.0.2013-01-19

agent.sources.s0.interceptors = logIntercept

agent.sources.s0.interceptors.logIntercept.appId = 153299

agent.sources.s0.interceptors.logIntercept.env = SP

agent.sources.s0.interceptors.logIntercept.hostName = vm-e61b-fe34.nam.nsroot.net<http://vm-e61b-fe34.nam.nsroot.net>

agent.sources.s0.interceptors.logIntercept.logFileName = AggKeyListener.0.2013-01-19

agent.sources.s0.interceptors.logIntercept.logFilePath = /var/log/creditcard/

agent.sources.s0.interceptors.logIntercept.logType = creditcard log

agent.sources.s0.interceptors.logIntercept.type = com.citi.sponge.flume.agent.source.LogInterceptor$Builder

agent.sources.s0.type = exec

agent.sources.s1.batchSize = 1

agent.sources.s1.channels = fileChannel

agent.sources.s1.command = tail -F /var/log/creditcard/AggKeyListener.1.2013-01-19

agent.sources.s1.interceptors = logIntercept

NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB