samba - Oct 2017 - Linux vs. Windows SMB buffering

>
>
> Does the wireshark trace show the Windows client asking for and
> getting a RWH lease under SMB2 ? If so, then there's no reason
> it can't be caching the entire file locally. Seems strange
> behaviour from the Windows redirector here.
>
I have uploaded the Linux packet capture here (14MB):
https://drive.google.com/open?id=0B6UHr3GQEkQwWXJ1NjVwMkJXOEU

Also, here is the corresponding Windows packet capture as well (375MB):
https://drive.google.com/open?id=0B6UHr3GQEkQwbFhOY0lCcEFjZkU
> Or alternatively, just use the Linux SMB client and don't port the
software to Windows :-).

You have no idea how much I wish that was possible :D I'm trying to slowly
convert my colleagues to Linux :)

Thanks for the quick reply!
Will

On Fri, Oct 06, 2017 at 07:26:29PM +0000, Will Lucas
wrote:
> 
>     Does the wireshark trace show the Windows client asking for and
>     getting a RWH lease under SMB2 ? If so, then there's no reason
>     it can't be caching the entire file locally. Seems strange
>     behaviour from the Windows redirector here.
> 
> 
> I have uploaded the Linux packet capture here
(14MB): https://drive.google.com/
> open?id=0B6UHr3GQEkQwWXJ1NjVwMkJXOEU
> 
> Also, here is the corresponding Windows packet capture as well
(375MB): https:/
> /drive.google.com/open?id=0B6UHr3GQEkQwbFhOY0lCcEFjZkU
> to Windows :-).
The Linux client is asking for SMB1 and using 1MB write sizes.

The Windows client is using SMB2 and *NOT ASKING FOR LEASES*.

This is why the performance is terrible. Because the file
as no lease, the Windows redirector must pass every single
WriteFile() system call onto the wire, no matter how small
the size.

If you can get the Windows SMB2 client to request a lease,
the performance problem will be solved.

What is your server ? Is it Samba ? If so what version ?

> The Linux client is asking for SMB1 and using 1MB write sizes.
>
> The Windows client is using SMB2 and *NOT ASKING FOR LEASES*.
>
> This is why the performance is terrible. Because the file
> as no lease, the Windows redirector must pass every single
> WriteFile() system call onto the wire, no matter how small
> the size.
>
> If you can get the Windows SMB2 client to request a lease,
> the performance problem will be solved.
Jeremy,

Thanks for the response that's definitely more information than I've
been
able to find over the past year!
> What is your server ? Is it Samba ? If so what version ?
My NAS is a Synology DS215j and it is running Samba. smbd -V gives me the
following:
Version 4.4.13
Synology Build 15152, Jul 13 2017 04:48:37

So, this morning I ran a test by enabling leases, which were not enabled on
the server before. So, now my smb.conf looks like this:
[global]
printcap name=cups
winbind enum groups=yes
include=/var/tmp/nginx/smb.netbios.aliases.conf
min protocol=NT1
socket options=TCP_NODELAY IPTOS_LOWDELAY SO_RCVBUF=65536 SO_SNDBUF=65536
security=user
local master=no
realm=*
use sendfile=yes
min receivefile size=16384
passdb backend=smbpasswd
write cache size=2097152
smb2 leases=yes
printing=cups
max protocol=SMB3
winbind enum users=yes
getwd cache=true
load printers=yes
workgroup=WORKGROUP

I noticed now that the packet capture shows Negotiate Protocol Response
conversations between the server and the Windows client. It also seems the
client is now using a lease.  Unfortunately, the Windows client is still
immediately writing one line at a time :(

I have uploaded the new packet capture snippet here (2MB):
https://drive.google.com/open?id=0B6UHr3GQEkQwcXdEWVRFSXRMNnc

Hopefully, I'm getting closer? :) Does the smb.conf looks reasonable to you?

Thanks again for all your help, it's greatly appreciated!
Will

On Fri, Oct 6, 2017 at 7:09 PM Jeremy Allison <jra at samba.org> wrote:
> On Fri, Oct 06, 2017 at 07:26:29PM +0000, Will Lucas wrote:
> >
> >     Does the wireshark trace show the Windows client asking for and
> >     getting a RWH lease under SMB2 ? If so, then there's no reason
> >     it can't be caching the entire file locally. Seems strange
> >     behaviour from the Windows redirector here.
> >
> >
> > I have uploaded the Linux packet capture here (14MB):
> https://drive.google.com/
> > open?id=0B6UHr3GQEkQwWXJ1NjVwMkJXOEU
> >
> > Also, here is the corresponding Windows packet capture as well
> (375MB): https:/
> > /drive.google.com/open?id=0B6UHr3GQEkQwbFhOY0lCcEFjZkU
> > to Windows :-).
>
> The Linux client is asking for SMB1 and using 1MB write sizes.
>
> The Windows client is using SMB2 and *NOT ASKING FOR LEASES*.
>
> This is why the performance is terrible. Because the file
> as no lease, the Windows redirector must pass every single
> WriteFile() system call onto the wire, no matter how small
> the size.
>
> If you can get the Windows SMB2 client to request a lease,
> the performance problem will be solved.
>
> What is your server ? Is it Samba ? If so what version ?
>