[gpfsug-discuss] SMB performance issues with CES

[Jan-Frode Myklebust]

Sorry, I don't know.

I tried checking, and it looks like signing is disabled by default in
the linux cifs module:

cifsfs.c:MODULE_PARM_DESC(enable_negotiate_signing, "Enable
negotiating packet signing algorithm with server. Default: n/N/0");

Elsewhere I find that mount option sec=ntlmssp also might influence
this to only do signing if server requires it..


  -jf

On Mon, Jun 1, 2026 at 5:39 PM Leonardo Sala <leonardo.sala at psi.ch> wrote:
>
> Hi Jan-Frode
>
> interesting! Is this something I could apply to the linux clients, too, or is this only for windows clients?
>
> cheers
>
> leo
>
> Paul Scherrer Institut
> Dr. Leonardo Sala
> Group Leader Data Analysis and Research Infrastructure
> Group Leader Data Curation a.i.
> Deputy Department Head Science IT Infrastructure and Services department
> Science IT Infrastructure and Services department (AWI)
> OBBA/230
> Forschungstrasse 111
> 5232 Villigen PSI
> Switzerland
>
> Phone: +41 56 310 3369
> leonardo.sala at psi.ch
> www.psi.ch
>
> On 6/1/26 15:24, Jan-Frode Myklebust wrote:
>
> Not too long ago there were some reports about SMB signing being very
> costly. Signing would give approximately 500 MB/s, while encryption
> would give closer to 1200 MB/s. Signing is controlled by Security
> Settings -> Local Policies -> Security options "Microsoft network
> client: Digitally Sign Communications (always)".
>
>
>   -jf
>
> On Mon, Jun 1, 2026 at 2:24 PM Leonardo Sala via gpfsug-discuss
> <gpfsug-discuss at gpfsug.org> wrote:
>
> Hallo everyone
>
> I have just notices some possible performance issues on SMB when using CES, at least compared to NFS. Using NFSv4 I can easily get 1 GB/s on a single client (linux), while when using a CIFS mount I get tops 500 MB/s on a single client. Using two separate servers as clients gets a 1 GB/s total throughput on the CES server, so I would say there not a strict limitation on the CES server itself. Any hints on how to improve this / debugging hints? I spent some time on IBM documentation and some user groups talks, but got no improvement...
>
> Thanks!
>
> cheers
>
> leo
>
> --
> Paul Scherrer Institut
> Dr. Leonardo Sala
> Group Leader Data Analysis and Research Infrastructure
> Group Leader Data Curation a.i.
> Deputy Department Head Science IT Infrastructure and Services department
> Science IT Infrastructure and Services department (AWI)
> OBBA/230
> Forschungstrasse 111
> 5232 Villigen PSI
> Switzerland
>
> Phone: +41 56 310 3369
> leonardo.sala at psi.ch
> www.psi.ch
>
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