samba - May 2021 - Samba share for HPC environment.

On Mon, May 24, 2021 at 3:48 PM Jeremy Allison <jra at samba.org> wrote:
> On Mon, May 24, 2021 at 03:37:47PM -0300, Daniel Lopes de Carvalho wrote:
>
> >The outage occurs between headnode server and clients desktops (Windows
7,
> >10, Server 2012 and 2019) only.
>
> How long does the outage last ?
Extremely short, but it is enough to cause problems in the running
software.

> What is causing it ?
My guess is that the write operation (with multiple opened network
connections) of this software.

> Does it cause TCP connection failure between client and headnode ?
>
Yes

>
> Eliminating or finding the cause of this would seem to
> be the quickest way to success.
>

-- 
Daniel Lopes de Carvalho
daniel at cepetro.unicamp.br
unisim.cepetro.unicamp.br <https://www.unisim.cepetro.unicamp.br/>
+55 19 3521-1221

On Wed, May 26, 2021 at 01:34:56PM -0300, Daniel Lopes de Carvalho
wrote:
>On Mon, May 24, 2021 at 3:48 PM Jeremy Allison <jra at samba.org>
wrote:
>
>> On Mon, May 24, 2021 at 03:37:47PM -0300, Daniel Lopes de Carvalho
wrote:
>>
>> >The outage occurs between headnode server and clients desktops
(Windows 7,
>> >10, Server 2012 and 2019) only.
>>
>> How long does the outage last ?
>
>Extremely short, but it is enough to cause problems in the running
>software.
>
>
>> What is causing it ?
>
>My guess is that the write operation (with multiple opened network
>connections) of this software.
>
>
>> Does it cause TCP connection failure between client and headnode ?
>>
>Yes
OK, if the outage is short, then Samba supports durable handles
which should allow recovery.

 From the smb.conf man page.

        durable handles (S)

            This boolean parameter controls whether Samba can grant SMB2 durable
file handles on a share.

            Note that durable handles are only enabled if kernel oplocks = no,
kernel share modes = no, and posix locking = no, i.e. if the share is
            configured for CIFS/SMB2 only access, not supporting
interoperability features with local UNIX processes or NFS operations.

            Also note that, for the time being, durability is not granted for a
handle that has the delete on close flag set.

            Default: durable handles = yes

Note that you'll need "kernel oplocks = no, kernel share modes = no,
and posix locking = no".