[Samba] Multichannel working at half speed with 2x NICs

[Kanchana Marasinghe]

Hi Jeremy,

Is it safe to assume it's just "strace -p <pid>", for the running samba
daemon?
Regards
Kanchana

On Wed, Sep 28, 2016, 1:00 PM Jeremy Allison <jra at samba.org> wrote:

> On Wed, Sep 28, 2016 at 05:56:24AM +0000, Kanchana Marasinghe via samba
> wrote:
> > Similar to another thread that was posted recently (archive:
> > https://groups.google.com/forum/#!topic/linux.samba/sRvmCb25U_s) I'm
> trying
> > to get multichannel working with a virtual Linux server running version
> > 4.4.5.
> >
> > Output of 'uname -a': "Linux filehost 4.4.0-38-generic #57-Ubuntu SMP Tue
> > Sep 6 15:42:33 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux"
> >
> > I have two VirtIO NICs on my server that I've confirmed works at at
> least 1Gbps
> > (via iperf) to my Windows 10 client which also has 2 1Gbps NICs. Since
> virtio
> > interfaces dont seem to report link speeds, I've changed my smb.conf to
> > reflect this as such:
> >
> > "interfaces = 192.168.1.120;speed=1000000000
> 192.168.1.118;speed=1000000000"
> >
> > I've also tried with and without "aio read size = 1" and "aio write size
> =
> > 1", but that didn't change anything. In addition, I've tried all the
> > suggestions in thread linked above and all have been unsuccessful.
> >
> > I've verified that all my drives on both the server and client are
> capable
> > of sustaining read/writes of well over 250MB/s, so I don't think this is
> a
> > disk bottleneck issue.
> >
> > What happens during a file transfer is that both interfaces are only
> > utilized at around 50%, so they both combine to give me ~1Gbps, when they
> > really should be working at 100% each for ~2Gbps total.
> >
> > What can I do to troubleshoot this?
>
> strace the connected smbd to ensure it's using the pthreadpool.
>