AIO, SMB2 and Samba 3.6

Andrew Bartlett abartlet at
Wed Feb 22 04:16:14 MST 2012

On Wed, 2012-02-22 at 10:54 +0100, Volker Lendecke wrote:
> On Wed, Feb 22, 2012 at 03:56:52PM +1100, Andrew Bartlett wrote:
> > I've now reproduced this on the NAS with a level 10 log, using
> > smbclient4 from master:
> > 
> > bin/smbclient // -Uuser%password
> > smb: \> put /data/kvm/cdroms/FreeBSD-8.2-RELEASE-amd64-bootonly.iso
> > freebsd7.iso
> > Error writing file: socket_error
> > 
> > It seems to me that the underlying AIO layer isn't returning promptly or
> > correctly.  It appears that after the socket error, smbclient still
> > tries to close the file, and this then triggers finally an AIO error. 
> The reference to freebsd makes me wonder if the NAS box
> might be FreeBSD based. 

Sorry for the red herring.  That was just a 50MB file I had lying
around.  It is Linux and glibc 2.7-18lenny7.

> I think I've seen problems with
> Samba setting up the RT signal we choose for AIO. It should
> have disabled using aio. Can you check further up in the log
> whether that might be the case? 

This certainly matches the symptoms: what would the message be in that
case?  The log is the full log from the point of the share connection. 

> Also, you might try the
> aio_fork and aio_pthread modules.

Indeed, given the well known performance issues with glibc AIO
aio_pthread has already been recommended.  This task was just to first
sort out (if possible) why the default aio didn't work at all.


Andrew Bartlett

Andrew Bartlett                      
Authentication Developer, Samba Team 

More information about the samba-technical mailing list