Re: [JSch-users] JSch: Too many open files

[Maximilien R. <iix...@gm...>]

Hello !


First of all, thanks for the really quick answer.

I checked the version and the server we're using for the tests has
OpenSSH_4.7p1 and Ubuntu 8.04 LTS. I've tested on another server with 5.1
and it did work. The server is also significantly slower to respond because
it's at home and on a regular ADSL connection. However, I do not think that
makes any difference if the connection is slower as, yesterday, I
voluntarily tried to limit the number of connection per second and it still
did crash after a approximatively the same number of overall connections.

I guess that it is in fact an OpenSSH bug which is solved in newer versions.


Thanks once again for your answer !


Best regards,


Ir Maximilien Renard

P.S. In case the problem should still be observed when we will upgrade our
test server, I will of course report back.

On 17 April 2012 09:29, Atsuhiko Yamanaka <ym...@jc...> wrote:

> Hi,
>
>   +-From: Maximilien Renard <iix...@gm...> --
>   |_Date: Mon, 16 Apr 2012 18:20:33 +0200 __________
>    |
>
>   |Saddly, as I started stress-testing the application, I've noticed
>   |that after a certain number of file SFTP transfer, the library
>   |"crashes" with the following message:
>
>   |1: Caught an exception, leaving main loop due to SSH_MSG_DISCONNECT: 2
>   |Could not create socket pairs: Too many open files
>   |1: Disconnecting from 195.244.167.187 port 10004
>
> It seems "socket pairs" means the Unix domain sockets for the communication
> between "sshd" and "/usr/libexec/openssh/sftp-server", and it has been
> failed
> to create them due to "Too many open files", as the message says.
>
> At least, I guess that you can work around that error if the channel is
> re-used without invoking "closeAndDisconnectSftpChannel()".
>
> As for the problem, I have confirmed that the following chunk of code
> will cause the reported error for sftp-server of OpenSSH 4.3p2,
>
>      for(int i = 0; i< 1024; i++){
>        try{
>          ChannelSftp c = (ChannelSftp)session.openChannel("sftp");
>          c.connect();
>          c.disconnect();
>        }
>        catch(Exception e){
>          System.out.println("i: "+i+" "+e);
>          break;
>        }
>      }
>
> However, I could not reproduce it for sftp-server of OpenSSH 5.3p1.
>
> Which OpenSSH version are you using?  Frankly to say, I have not found
> the problem in JSch yet, and have suspected that the older OpenSSH versions
> may have the resource leaks in managing Unix sockets.
>
>
> Sincerely,
> --
> Atsuhiko Yamanaka
> JCraft,Inc.
> 1-14-20 HONCHO AOBA-KU,
> SENDAI, MIYAGI 980-0014 Japan.
> Tel +81-22-723-2150
> Skype callto://jcraft/
> Twitter: http://twitter.com/ymnk
> Facebook: http://facebook.com/aymnk
>



-- 
Ir Maximilien Renard

mr...@eu...
mr...@ki...