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From Koji Kawamura <>
Subject Re: Slow FTP and SFTP nifi transfer rates
Date Thu, 07 Sep 2017 23:48:25 GMT

Thanks for clarifying that the number of files is not significant.
I looked at the PutFTP and FTPTransfer source code, and found that it
makes few calls to a FTP server in addition to send a file:

1. Sending a file as a temporal file
2. Update modification time, if 'Last Modified Time' is set
3. chmod if 'Permissions' is set
4. Rename the temporal file

PutSFTP and SFTPTransfer does followings additionally:
5. chown if 'Remote Owner' is set
6. chgrp if 'Remote Group' is set

I wonder if those additional invocations add more latency.

Also, it'd be helpful if you can write simple Java code using the
underlying (S)FTP client libraries without NiFi layer to investigate
if NiFi implementation can be improved, or the performance difference
come from library implementation. for FTP
jsch-0.1.54::com.jcraft.jsch.ChannelSftp for SFTP

I will try to do that at my end when I have time, but it'd be very
helpful if you can do that since you already have testing environment
and base metrics.


On Thu, Sep 7, 2017 at 6:30 PM, Gino Lisignoli <> wrote:
> Hi
> I monitor the send rates using collectd and grafana. It doesn't seem to
> matter if I send 10,000 10MB files or 100 1GB files, the maximum throughput
> rate of nifi PutFTP and PutSFTP remain the same. 300Mbps and 1Gbs
> As mention above, the weird thing is when I send files though ftp and sftp
> (without nifi) then the rates are much better.
> It's really odd the the rates are significantly slower in NIFI.
> On Thu, Sep 7, 2017 at 5:45 PM, Koji Kawamura <>
> wrote:
>> Hello Gino,
>> Thanks for sharing your findings on FTP performance.
>> How did you measure send rate from NiFi to your FTP server?
>> Sending multiple FlowFiles would provide less throughput compared to
>> sending one big FlowFile, as PutFTP and PutSFTP make connection to
>> each incoming FlowFile. The overhead of establishing connection each
>> time might be the performance difference you see with mput command.
>> Those processors can decide which FTP servers to use based on incoming
>> FlowFiles' attribute when NiFi Expression Language is used.
>> If that's the case, there are some room for performance improvement by
>> keeping underlying FTP(S) client instance so that it can be reused
>> among multiple onTrigger() call.
>> A possible work-around would be using MergeContent beforehand and send
>> it as a single file, if your use-case allows that.
>> Thanks,
>> Koji
>> On Thu, Sep 7, 2017 at 12:15 PM, Gino Lisignoli <>
>> wrote:
>> > I have this weird issue with PutFTP and PutSFTP transfer rates.
>> >
>> > What I am seeing is that no matter what files I transfer from One server
>> > to
>> > another over a single connection the maximum rates I can send are
>> > 300Mbps
>> > for PutFTP and 1Gbps for PutSFTP.
>> >
>> > The sending nifi is installed on Centos 7, running on a Dell R730, 190GB
>> > Ram, 16 Cores @ 2.4GHz and 4x10Gb nics bonded. The sending nifi has it's
>> > content repository on a ramdisk, and the receiving server is receiving
>> > to a
>> > ramdisk (for testing, to remove disk IO out of the equation).
>> >
>> > When I do a ftp send manually (without nifi) with mput I get ftp rates
>> > of
>> > ~8Gbs and sftp rates of 2.2Gbs (Which seems slow anyway).
>> >
>> > I would have expected transfer rates similar with nifi.
>> >
>> > Is there any way to work out why these rates are so much slower, but
>> > also so
>> > consistent? I'm using Nifi-1.30

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