Would you be able to attach using jmx with jconsole(or similar) and
check out the numbers you are getting for events delivered/number of
batches(there are beans exposing these values for sink/channel/source)?
If I can, I'll try to recreate your scenario when I have some time, but
that's not happening right now, sorry
On 09/05/2012 03:05 PM, Jagadish Bihani wrote:
Hi Juhani
Thanks for the inputs.
I did following changes:
-- I sent my string event to socket with batches of 1000 & 10000 of
such events.
-- I have also started using DEBUG log level for flume agent.
-- I have also increased max-line-length property of netcat source
from default 512.
But both problems remained. Events got lost without any exception.
And performance also didn't get improve much (from 1 KB/sec now it's
1.3 KB/sec apprx).
Is there anything else to be considered?
Regards,
Jagadish
On 09/04/2012 04:40 PM, Juhani Connolly wrote:
Hi Jagadish,
NetcatSource doesn't use any batching when receiving events. It
writes one event at a time, and that translates in the FileChannel to
a flush to disk, so when you're writing many, your disk just won't
keep up. One way to improve this is to use separate physical disks
for your checkpoint/data directories.
TailSource used to have the same problem until we added batching to
it. By a cursory examination of NetcatSource, it looks to me like you
can also force some batching by sending multiple lines in each
socket->send.
As to the first problem with lines going missing, I'm not entirely
sure as I can't dive deeply into the source right now. I wouldn't be
surprised if it's some kind of congestion problem and lack of
logging(or your log levels are just too high, try switching them to
INFO or DEBUG?) that will be resolved once you get the throughput up.
On 09/04/2012 07:50 PM, Jagadish Bihani wrote:
Hi
I encountered an problem in my scenario with netcat source. Setup is
Host A: Netcat source -file channel -avro sink
Host B: Avro source - file channel - HDFS sink
But to simplify it I have created a single agent with "Netcat
Source" and "file roll sink"*
*It is *:
*Host A: Netcat source - file channel - File_roll sink
*Problem*:
1. To simulate the our production scenario. I have created a script
which runs for 15 sec and in the
while loop writes requests netcat source on a given port. For a
large value of the sleep events are
delivered correctly to the destination. But as I reduce the delay
events are given to the source but they
are not delivered to the destination. e.g. I write 9108 records
within 15 sec using script and only 1708
got delivered. And I don't get any exception. If it is flow control
related problem then I should have seen
some exception in agent logs. But with file channel and huge disk
space, is it a problem?
*Machine Configuration:*
RAM : 8 GB
JVM : 200 MB
CPU: 2.0 GHz Quad core processor
*Flume Agent Confi**guration*
adServerAgent.sources = netcatSource
adServerAgent.channels = fileChannel memoryChannel
adServerAgent.sinks = fileSink
# For each one of the sources, the type is defined
adServerAgent.sources.netcatSource.type = netcat
adServerAgent.sources.netcatSource.bind = 10.0.17.231
adServerAgent.sources.netcatSource.port = 55355
# The channel can be defined as follows.
adServerAgent.sources.netcatSource.channels = fileChannel
#adServerAgent.sources.netcatSource.channels = memoryChannel
# Each sink's type must be defined
adServerAgent.sinks.fileSink.type = file_roll
adServerAgent.sinks.fileSink.sink.directory = /root/flume/flume_sink
#Specify the channel the sink should use
#adServerAgent.sinks.fileSink.channel = memoryChannel
adServerAgent.sinks.fileSink.channel = fileChannel
adServerAgent.channels.memoryChannel.type =memory
adServerAgent.channels.memoryChannel.capacity = 100000
adServerAgent.channels.memoryChannel.transactionCapacity = 10000
adServerAgent.channels.fileChannel.type=file
adServerAgent.channels.fileChannel.dataDirs=/root/jagadish/flume_channel1/dataDir3
adServerAgent.channels.fileChannel.checkpointDir=/root/jagadish/flume_channel1/checkpointDir3
*Script snippet being used:*
...
eval
{
local $SIG{ALRM} = sub { die "alarm\n"; };
alarm $TIMEOUT;
my $i=0;
my $str = "";
my $counter=1;
while(1)
{
$str = "";
for($i=0; $i < $NO_ELE_PER_ROW; $i++)
{
$str .= $counter."\t";
$counter++;
}
chop($str);
#print $socket "$str\n";
$socket->send($str."\n") or die "Didn't send";
if($? != 0)
{
print "Failed for $str \n";
}
print "$str\n";
Time::HiRes::usleep($SLEEP_TIME);
}
alarm 0;
};
if ($@) {
......
- Script is working fine as for the very large delay all events are
getting transmitted correctly.*
*- Same problem occurs with memory channel too but with lower values
of sleep.*
**Problem 2:*
-- With this setup I am getting very low throughput i.e. I am able
to transfer only ~ 1 KB/sec data
to the destination file sink. Similar performance was achieved using
HDFS sink.
-- I had tried increasing batch sizes in my original scenario
without much gain in throughput.
-- I had seen using 'tail -F' as source almost 10 times better
throughput.
-- Is there any tunable parameter for netcat source?
Please help me in above 2 cases - i)netcat source use cases
ii) Typical flume's expected throughput with file channel and
file/HDFS sink on the single machine.
Regards,
Jagadish
