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From Robert B Hamilton <robert.hamil...@gm.com>
Subject RE: HDFS Sink performance
Date Wed, 22 Jul 2015 16:00:04 GMT
 I only see that kind of throughput for event sizes of 25kB to 50kB or larger.

These particular tests are done on flume version 1.3.1.
But because you asked,  I thought to do a few quick runs on 1.5.0.1 and added those results
below.  The results are significantly different for 1.5 and I wonder if this is a cause for
concern.

None of this has been peer reviewed so it should be considered as tentative.

As to the HDD, here is result of a quick and dirty dd test.

  dd if=/dev/zero of=100M bs=1M count=100 conv=fsync oflag=sync
   104857600 bytes (105 MB) copied, 0.685646 s, 153 MB/s


Source data: each record consists of random ascii strings of constant length (25k,50k,or 80k
depending on the run).
Source: spooldir
Channel: file channel single dataDir, or memory channel.
Sink: four HDFS, SequenceFile, Text, Batch size=10, rollInterval=20 seconds.

Batch size was kept small because of memory channel capacity. Increasing batch size for file
channel did not improve performance so I kept it at 10.

Here I have numbers for some runs where the payload is varied from 25K,50K, and 80K. I include
memory channel for comparison.

Multiple runs were peformed for each event size. As you can see the throughput can vary from
run to run because these particular measurements were done on an environment that is not tightly
controlled.  Think of them as "in situ" measurements :)

Flume 1.3.1 memory channel and file channel
-------------------------------------------------------
Payload  Rate memch Rate(filechl)
(kB)(MB/s)       (MB/s)
-----------------------------------------------------
253429
253127.6
255023.3
2546.527.2
5031.223.8
5037.431.3
5032.331.8
8030.525.8
8046.225.2
8039.125.8
8056.525.1


Flume 1.5 File Channel and Memory Channel
---------------------------------------------------
Event size  Rate memch Rate filech
(KB)        (MB/s)  (MB/s)
---------------------------------------------------
2518.715.6
5018.317.3
8018.415.6

-----Original Message-----
From: Roshan Naik [mailto:roshan@hortonworks.com]
Sent: Friday, July 17, 2015 6:21 PM
To: user@flume.apache.org
Subject: Re: HDFS Sink performance

I Updated the Flume wiki with my measurements. Also added section with Hive sink measurements.

https://cwiki.apache.org/confluence/display/FLUME/Performance+Measurements+
-+round+2


@Robert:
  What sort of a HDD are you using ?
  What is event size ?
  Which version of flume ?

-roshan




On 7/17/15 12:51 PM, "Robert B Hamilton" <robert.hamilton@gm.com> wrote:

>Our testing has shown up to 60MB/s to HDFS if we use up to 8 or 10
>sinks per agent, and with a file channel with a single dataDir.
>
>
>From: lohit [mailto:lohit.vijayarenu@gmail.com]
>Sent: Wednesday, July 15, 2015 11:11 AM
>To: user@flume.apache.org
>Subject: HDFS Sink performance
>
>Hello,
>
>Does anyone have some numbers which they can share around HDFS sink
>performance. From our testing, for single sink writing to HDFS
>(CompressedStream) and reading from MemoryChannel can only do about
>35000 events per second (each event is about 1K) in size. After
>compression this turns out to be ~10MB/s write stream to HDFS file.
>Which is pretty low. Our configuration looks like this
>
>agent.sinks.hdfsSink.type = hdfs
>agent.sinks.hdfsSink.channel = memoryChannel
>agent.sinks.hdfsSink.hdfs.path = /tmp/lohit
>agent.sinks.hdfsSink.hdfs.codeC = lzo
>agent.sinks.hdfsSink.hdfs.fileType = CompressedStream
>agent.sinks.hdfsSink.hdfs.writeFormat = Writable
>agent.sinks.hdfsSink.hdfs.rollInterval = 3600
>agent.sinks.hdfsSink.hdfs.rollSize = 1073741824
>agent.sinks.hdfsSink.hdfs.rollCount = 0
>agent.sinks.hdfsSink.hdfs.batchSize = 10000
>agent.sinks.hdfsSink.hdfs.txnEventMax = 10000
>
>agent.channels.memoryChannel.type = memory
>
>agent.channels.memoryChannel.capacity = 3000000
>agent.channels.memoryChannel.transactionCapacity = 10000
>
>--
>Have a Nice Day!
>Lohit
>
>
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