samba - Mar 2016 - /etc/msg.sock folder questions regarding nvram/wear leveling.

Hi,

i try to create a openWRT Samba 4.3 package and stumbled across the fact
that samba 4.3 will create those message socks inside the private-dir. That
results in creating entries inside /etc/samba/msg.sock.

On openWRT /var is a tempFS in ram, so anything there is not a problem
regarding nvram and wear leveling. Yet the root uses a jffs2 overlay. So
while those message socks have no size, jffs2 still needs to write the dir
table, since they survive a reboot.

I'm now wondering how frequently those sock entries are created/deleted
while running samba? In my tests the msg.sock folder kept growing over time
from 3-4 entries to 8/12 ?

Maybe its reasonable to allow /etc/msg.sock to also reside inside the /var
folder, with some extra "dir-xy" configure option or/and smb.conf?

bye
Andy

On 11/03/16 12:08, Andy Walsh wrote:
> Hi,
>
> i try to create a openWRT Samba 4.3 package and stumbled across the fact
> that samba 4.3 will create those message socks inside the private-dir. That
> results in creating entries inside /etc/samba/msg.sock.
>
> On openWRT /var is a tempFS in ram, so anything there is not a problem
> regarding nvram and wear leveling. Yet the root uses a jffs2 overlay. So
> while those message socks have no size, jffs2 still needs to write the dir
> table, since they survive a reboot.
>
> I'm now wondering how frequently those sock entries are created/deleted
> while running samba? In my tests the msg.sock folder kept growing over time
> from 3-4 entries to 8/12 ?
>
> Maybe its reasonable to allow /etc/msg.sock to also reside inside the /var
> folder, with some extra "dir-xy" configure option or/and
smb.conf?
>
> bye
> Andy
>
>
You can choose a different directory, you don't have to use '/var'.
I
take it you are compiling Samba yourself, so try running './configure 
--help' inside the tarballs base directory.

Rowland

Rowland penny <rpenny <at> samba.org> writes:
> 
> On 11/03/16 12:08, Andy Walsh wrote:
> > Hi,
> >
> > i try to create a openWRT Samba 4.3 package and stumbled across the
fact
> > that samba 4.3 will create those message socks inside the private-dir.
That
> > results in creating entries inside /etc/samba/msg.sock.
> >
> > On openWRT /var is a tempFS in ram, so anything there is not a problem
> > regarding nvram and wear leveling. Yet the root uses a jffs2 overlay.
So
> > while those message socks have no size, jffs2 still needs to write the
dir
> > table, since they survive a reboot.
> >
> > I'm now wondering how frequently those sock entries are
created/deleted
> > while running samba? In my tests the msg.sock folder kept growing over
time
> > from 3-4 entries to 8/12 ?
> >
> > Maybe its reasonable to allow /etc/msg.sock to also reside inside the
/var
> > folder, with some extra "dir-xy" configure option or/and
smb.conf?
> >
> > bye
> > Andy
> >
> >
> 
> You can choose a different directory, you don't have to use
'/var'. I
> take it you are compiling Samba yourself, so try running './configure 
> --help' inside the tarballs base directory.
> 
> Rowland
> 
I'm specifically asking about the msg.sock, not the msg.lock entries. The
msg.sock entries are created under the priv-dir, where also all the
important pdb/tdb files reside. So i can't move the msg.sock folder to /var,
since its coded to use the priv-dir. I assume this is fine under normal
circumstances, i just wonder if this is a good location on openWRT and
embedded platforms?

I assume in contrast to the pdb/tdb files, the msg.sock entries are
created/deleted more frequently. So writing a new tdb file once a day/week
is reasonable on raw nvram, changing folders/files every few minutes could
be problematic. Thats because atm jffs2 on raw nvram can't handle bad blocks
on those devices, so if possible anything that could be moved to /var and
does not need to survive a reboot should be moved to this location.

So the main question would be how frequently are those msg.sock entries
created/deleted? Is it once per smbd start or dependent on what other factors?

thx
Andy