Re: Remote SFTP File Open (SSH_FXP_OPEN) speed optimisations

[Jakub Jelen <jjelen@xxxxxxxxxx>]

On Mon, 2020-06-15 at 14:46 +0000, Does Itwork wrote:
>  Understood. To help rule out any client side causes, what's the best
> way to figure out where the libssh part of our client is spending
> time when sending & receiving the response to a file open request on
> the remote server?
> Unfortunately we have no access to the server (it belongs to an
> external third party), though we believe it is an IBM product.
> Many thanks.

The easiest would be checking some profilling tools, but the client
should be really sending just a request and wait for confirmation from
server and if the delay comes from the server, it is hard to help.

Additionally, you can try different SFTP clients to see if you
encounter similar delay with the same server.

Jakub

>     On Monday, 15 June 2020, 10:40:57 BST, Jakub Jelen <
> jjelen@xxxxxxxxxx> wrote:  
>  
>  On Fri, 2020-06-12 at 14:55 +0000, Does Itwork wrote:
> > Hi, 
> > 
> > Are there any tricks or settings in libssh that could speed up slow
> > file opens of a new file on a remote sftp server?
> > When we retrieve files in a time sensitive application using
> > libssh,
> > the sftp file open command(SSH_FXP_OPEN) takes much longer to
> > complete than the actual read(SSH_FXP_READ) of a small amount of
> > data
> > from the file (50-100 bytes)  - open: 16-60ms vs read: <2ms.
> > Many thanks.
> 
> Hi,
> this will probably depend on your sftp server implementation and will
> certainly need some more investigation where the server (or client)
> is
> spending time when processing (or sending) this request.
> 
> Regards,
-- 
Jakub Jelen
Senior Software Engineer
Security Technologies
Red Hat, Inc.