[Samba] Linux requirements to support Multichannel

Anoop C S anoopcs at redhat.com
Thu Feb 23 10:34:55 UTC 2017

On Wed, 2017-02-22 at 17:54 +0530, Madhusudan R via samba wrote:
> Hi,
> Can someone point me to the list of pre-requisites from a linux box
> (preferably a VM) for Samba to support SMB Multichannel?
> For instance, if multiple interfaces are needed, then should they be of the
> same type, speed etc?

My thoughts(someone please correct me if I am wrong):

As explained in various docs which details the working of SMB Multi-channel, multiple interfaces is
not a hard requirement. In theory a single RSS/RDMA capable interface is enough for SMB client to
automatically detect and use network connection for Multi-channel if properly configured. It is the
client who decides on how to use the list of interfaces returned by server based on type(RSS or
RDMA) and speed. Judging from the docs, faster interfaces are always preferred and network
interfaces of same type and speed will be used simultaneously(obviously if slower interfaces are
present, it may not be used at all). SMB Multi-channel is also the feature responsible for detecting
the RDMA capabilities of network interfaces to enable SMB Direct(still under development in Samba).

Support for Multi-channel in Samba right now is experimental in nature and is not enabled by
default. See section "server multi channel support" and "interfaces" under man page for smb.conf(5)
for more details on how to configure Samba in order to achieve this feature. 

On the other side, your valuable testing results are always appreciated...

> Thanks,
> Madhu

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