[Samba] sysvol files - 'The data area passed to a system call is too small'

[Jonathan Hunter]

Hi Rowland

On 28 April 2018 at 09:17, Rowland Penny via samba <samba at lists.samba.org>
wrote:

> On Fri, 27 Apr 2018 22:40:41 +0100
> Jonathan Hunter via samba <samba at lists.samba.org> wrote:
>
> > OK - some more detail I have found in the meantime.
> >
> > I have compiled & ran listxattr, and I can now see a difference
> > between a working and a broken file:

[...]

Are you sure your sync method is working ?
> I ask this because the sysvol ACLs are stored in 'security.NTACL' and
> you don't have this on the non working DC
>

Thank you for the pointer, Rowland! Sometimes, what one person thinks is
'obvious' and 'clearly it can't be the fault of X'... turns out to not
quite be so obvious after all, and it really might be X at fault :)

I don't want to be too excited, because I have only just reconfigured
things and tried it once.. but with a sample size of one, it does seem to
work now!

I have given up on my multi-master replication using lsyncd.. and instead I
am running lsyncd only on DC1 (lsyncd uses inotify hooks to detect and then
push out any changes to sysvol via rsync to the other DCs). This means that
any sysvol / GPO changes need to be directed only against DC1 - which is
not ideal - but I would much rather have GPOs working than not :)

For what it's worth, my lsyncd.conf looks something like this below; there
is a pretty standard rsyncd.conf on the other end.

Rowland - do you think it's worth me writing up the lsyncd part for the
wiki? I'd be happy to put some text & guidance around it, it works well for
me as an inotify-driven rsync trigger (with of course the caveat that I now
don't think it works in a multi-master configuration)


-- automation from
https://gist.github.com/oscarssama/8bc223c8100890f71a07a5a6dc16a7f6
settings {
        statusFile = "/run/lsyncd-status.log",
        statusInterval = 10
}

targetList = {
        "1.1.1.1",
        "1.1.1.2",
        "1.1.1.3",
        "1.1.1.4"
}

for _, server in ipairs(targetList) do
        sync {
                default.rsync,
                source    = "/usr/local/samba/var/locks/sysvol/",
                target    = server .. "::_sysvol_/",
                rsync     = {
                        acls = true,
                        xattrs = true,
                        perms = true,
                        owner = true,
                        compress = true,
                        _extra = { "--numeric-ids" }
                }
        }
end

-- 
"If we knew what it was we were doing, it would not be called research,
would it?"
      - Albert Einstein