Slow performance listing huge number of files on Apache SSHD server

Hi Thomas,

I noted slow performance listing files on the front-end Apache SSHD server in the same scenario as https://issues.apache.org/jira/browse/SSHD-1215

The front-end Apache SSHD server is configured with a Filesystem built upon SFTPFileSystemProvider to proxy files to an Apache SSHD back-end server.

In the /inbox folder of the Apache SSHD backend server I have 2000 files.

The client sftp ls  commands take 2 secs on the backend Apache SSHD server, instead it takes about 48 secs on the front-end Apache SSHD server.

For greater number of files in the /inbox folder times are getting worse.

I have full traces of  sftp list commands to front-end Apache SSHD server that is attached to this jira.[^trace.frontend.sshd.log.zip]

I looked through the traces on the front-end server and it seems to me that for every files in the folder the sftp client on the front-end server creates a SSH_MSG_CHANNEL_DATA generating tcp traffic that slow down the performance of the list command.

Obviously this does not happen when a sftp client connects directly to the backend Apache SSHD server.

Can you take a look at traces on the front-end Apache SSHD server   ?

Do you think it's possbile change something to improve performance of list files in this situation ?

Thanks in advance

Kind Regards

Roberto