How to avoid client timeout.(SMB2 ECHO Request)

[Jones]

Hello Sandeep,

Just interesting,
if the client is windows-based OS, like Windows 7,
try to edit regedit to increase the SessTimeout value,
this workaround might ease the pain about this timeout issue.

My test environment set "strict allocate = yes",
uploading 20GB file and got this timeout issue,
windows client would prompt "Retry?" after 60sec.

It is likely if disk I/O is involved during allocation,
the response time takes more and longer latency.
And windows client thought it is timeout and re-negotiation.

After create this dword to with 120 value and reboot client,
it is okay to uploading 20GB file,
though the "Calculating..." remains for a while.

With wshark timestamp show that after setinfo request send out,
samba takes 102 seconds to send back setinfo response,
as Richard mentioned, how long it takes might also depend on back-end
capability.

I've tried "async smb echo handler = yes",
but still with no luck.

Hope this regedit would help.

Path:  \HKLM\SYSTEM\CurrentControlSet\Services\LanmanWorkstation\Parameters\
Name: SessTimeout
Type: DWORD
Value: 120 (unit is second)

Reference:
http://blogs.msdn.com/b/openspecification/archive/2013/03/27/smb-2-x-and-smb-3-0-timeouts-in-windows.aspx


-- 
Jones


2014-02-07 sandeep nag <sandeepnagamalli at gmail.com>:

> @Richard: Thank you, for the reply.
>
> Yes, sometimes in cases where box is in space-out situation, back-end
> write/truncate does take more that 60 sec in our back-end.
> Now in such scenarios where back-end is taking long time  > 60 sec, can we
> keep the samba connection alive by responding to Echo SMB2/CIFS client
> packets.
> Can we do this in VFS plugin reply function such as
> ocafs_ocafs_reply_commom().
>
>
> On Thu, Feb 6, 2014 at 10:41 PM, Richard Sharpe <
> realrichardsharpe at gmail.com
> > wrote:
>
> > On Thu, Feb 6, 2014 at 10:00 PM, sandeep nag <sandeepnagamalli at gmail.com
> >
> > wrote:
> > > http://msdn.microsoft.com/en-us/library/cc246540.aspx
> > >
> > > There is write/truncate request from the client and processing in samba
> > VFS
> > > plugin is taking longer time(which is expected as per our VFS plugin
> > > processing time).
> > > The client meanwhile sends many SMB ECHO requests
> > > (every 30 seconds (not sure)). However, they sit in the socket because
> > the
> > > smbd
> > > is now stuck and will only process the ECHOs after the truncate.
> Because
> > > of this, I am seeing client time outs.
> > >
> > > If the ECHO could be responded promptly, then the client would not
> time.
> > > How can this be done, please guide me in
> implementing/coding/undertanding
> > > this.
> >
> > Only you know the details of your back-end ... and I thought that it
> > did write-behind.
> >
> > In any event, if your back end is taking more than sixty seconds for a
> > write that is a problem, isn't it.
> >
> > Maybe you should ask Tarun.
> >
> > --
> > Regards,
> > Richard Sharpe
> > (何以解憂？唯有杜康。--曹操)
> >
>



-- 
Jones