Apache SSHD client performance

Question

I have an application using apache SSHD to send files via sftp (with the SftpClient class). I have noticed that the performance was very poor and I made a simple test comparing apache SSHD with Jsch, which gives much better results (seven times faster!) comparable with the openssh implementation.

Even though the performance can be partly improved (~30%) by changing the buffer size, for example, I haven't been able to match Jsch's performance by a long shot.

Has anybody noticed similar performance issues using apache SSHD as a client?

Do you have any suggestions to tune the performance, besides the buffer size?

Might be this: https://gist.github.com/int128/35501b5c09e92a24e6c2? — icyrock.com, Aug 10 '16 at 00:31
@icyrock.com you mean that SSHD has a poor performance in general (not only for the client) and that it might be due to them using SecureRandom? — Nicola Ambrosetti, Aug 10 '16 at 07:44
Looks like the link suggests that. I suggest using a profiler, that will give you an idea whether that is the issue or identify hotspot somewhere else. — icyrock.com, Aug 11 '16 at 02:57
Most likely they don't use packet pipelining on SSH or SFTP level. In general, optimizing SSH/SFTP is a tough job and I am not surprised that they didn't do their homework. — Eugene Mayevski 'Callback, Aug 14 '16 at 15:04
@EugeneMayevski'EldoS it seems then that Jsch did a better job somehow. — Nicola Ambrosetti, Aug 16 '16 at 08:56
Yes and they are not alone, eg. our Secureblackbox matches or outperforms openssh in speed. It's doable with some resource investment. — Eugene Mayevski 'Callback, Aug 16 '16 at 09:15

score 0 · Answer 1 · answered Apr 21 '20 at 13:18

The SFTP poor performances have been fixed as part of https://issues.apache.org/jira/browse/SSHD-979.

As Eugene hinted, packet pipelining was not implemented. This is the fact that when downloading, the client will ask for as much data as possible by issuing several read requests and keep a number of them running, so that it does not have to wait for a request to be received and written to disk before requesting more data. The same also affects upload as the client will send send several write requests instead of waiting for the server to acknowledge the request prior to sending a new one.

This is now fixed and SSHD performances are now at the same level as other implementations.

Apache SSHD client performance

1 Answers1