freebsd stable - Nov 2019 - Long-shot: repeatable macOS samba share unmounting during Lightroom import

Hi Chris,
> On 25 Nov 2019, at 05:12, Chris Gordon <chris at theory14.net> wrote:
> 
> WARNING:  Mostly deviating from a FreeBSD specific discion
> 
>> On Nov 23, 2019, at 9:33 PM, Andrew Reilly <areilly at
bigpond.net.au> wrote:
>> 
>> Hi all,
>> 
>> This is a long-shot question, because it involves a lot of moving
>> pieces, most of which are opaque commercial, poorly documented
>> things.  Never the less, it does involve FreeBSD-stable as one of
>> the players, and my experience over the years has been that FreeBSD
>> folk are both knowledgeable and helpful, so here's hoping.  Herwith
>> my tale of computer-induced irritation:
>> 
>> The story takes place at home, where the FreeBSD system in question
>> is a local network file server.  The FreeBSD tracks -STABLE every
>> week.  It boots from ZFS on NVM flash and has four 4TB Hitachi ATA
>> drives in a RAIDZ.  The current motherboard has a Ryzen 7 1700
>> 8-core locked at 3GHz by the bios to avoid a problem of going to
>> sleep permanently by failing to come out of some sort of low-power
>> state.  It has 32G RAM.  It has intel "PRO/1000 PCI-Express
Network
>> Driver" network connected to a simple gigabit switch, with both
>> IPv4 and IPv6 configured and working.
>> 
>> The other protagonist in this tale, also connected to the gigabit
>> LAN, is an iMac running current-Catalina on APFS flash, mounting
>> three filesystems over SMB, from Samba 4.10.10.  After appropriate
>> Samba tweaking this seems to be at least as reliable as it ever was
>> with netatalk or NFS, and apparently better supported by Apple.
>> 
>> I keep my Lightroom Classic catalogue on the mac's local (flash)
>> drive, but the photo storage is on the network.  The Import Backups
>> directory is also on (a different) network drive.  I use
Lightroom's
>> Import function to copy photos off SD cards using the mac's
built-in
>> SD card reader and register with the catalogue.  So far so normal,
>> I think.
>> 
>> The problem arose about ?three or four? months ago: could be
>> coincident with OS or Lightroom upgrades, I can't remember, but I
>> haven't changed anything about the setup, configuration or
workflow.
>> Now, every single time Lightroom does an import, while it's doing
>> the first scan of the SD card to identify photos that it's seen
>> before, all three of the Samba filesystems unmount from the mac,
>> silently.  I can find no record of error in any of the logs,
>> suggesting that the system thinks that it happened deliberately.
>> Needless to say, this throws out the import workflow, although it
>> manages to pick itself up OK if I just re-mount everything.
>> 
>> Anyone have any similar experiences?  Any thoughts of where I could
>> poke it to find out why this might be happening?  It feels like a
>> time-out bug somewhere, but (a) there is no complaint, and (b) the
>> network traffic is light at the time.  Needless to say Apple
>> documentation is useless.
>> 
>> Probably another good reason to find an alternative to Lightroom...
> 
> Other than the hardware specifics, I have the same exact workflow and same
players involved.
> 
> Maybe an odd question, but how are you mounting the SMB shares?
In the fallback instance, I mount them with Finder command-K (Go -> Connect
to Server).  Usually they mount automatically when I log in, because I have them
in my Startup Items.
> 
> Since updating to Catalina, I've found lots of problems dealing with
SMB using the Finder window and the items under the Locations side bar.  For
instance:
> - Mount a share.  At some point overnight when nothing is using it, the
share is unmounted.  I can't find anything in the logs to say why, when,
what, etc.  Just unmounted.
I haven't experienced any unattended unmounts.  Just during Lightroom
import.

I _have_ noticed (in Catalina, not before), that the Finder Sidebar does not
necessarily "keep up" with the mounted state of shares: after logging
in, I have seen my shared folders appear on the desktop as they open, but the
server listed in the side bar does not show the Eject icon that comes with being
mounted.
> - With a fresh start of the Finder process and I can access the SMB
server/shares.  After some time, activity, something, I only get
"Connection Failed" and can't access anything.  What's really
crazy, is that I can't even unmount mounted shares from under Locations when
it gets in this state (I can unmount via right click on the desktop item, CLI,
etc).  I see the share with the eject button, but just get useless error message
(if anything).
> - Killing (killall -HUP Finder) makes everything work again for a short
bit.
I've never been game to kill Finder from the command line.  If it comes to
that I just reboot the mac.  I figure there are so many daemon processes
involved these days that the chances of them not getting tangled on manual
intervention are slim.
> 
> If I mount the share via the Finder menubar (Go -> Connect to Server)
everything works and is rock solid.  Mounts with no problems, no mystery
unmount, etc.  I did test a Lightroom import and had no SMB issues when the
shared where mounted via the menu bar.
After writing my call for help, I took a couple of test photos and did another
import and nothing broke.  So perhaps there is an issue of import size, or an
issue with the first import after starting Lightroom, or something.  I'll be
doing more experimentation to see what specific issue triggers it.
> 
> I also store all of my music on the server and access it via SMB mounts. 
I've noticed that the Apple Music app will automatically mount the SMB share
when I hit play.  Unlike iTunes, I assume it's more aware of the filesystem
and mounts.  Even with the Finder window off in la-la land, the auto-mount by
Music works fine.  Now if this behavior could only be exposed to every other
app....
That sounds ominous.  I don't use the Apple Music app (Apple doesn't
understand FLAC), but a precedent of automatically mounting and (one assumes)
unmounting "media shares" could be a clue.
> 
> My completely un-researched guess is that when they removed the NetBIOS
support (one of the changes in Catalina), some bug was introduced or uncovered
causing the problematic behavior.  My guess ins based on the assumption that the
Finder window (not sure what to call it) displays all of the network browsing
and discovery and  is the code path that was impacted by the NetBIOS change. 
Any mount tied in with this path gets impacted, and when this goes south, it
takes the mounts with it.  Mounting via other means doesn't bring in the
associated path.
That sounds sort of plausible too.

FWIW I'm running Avahi on my FreeBSD system, and advertising the SAMBA
shares in the "apple-approved" way:

/user/local/etc/avahi/services/smb.service:
<?xml version="1.0" standalone='no'?>
<!DOCTYPE service-group SYSTEM "avahi-service.dtd">
<service-group>
 <name replace-wildcards="yes">%h</name>
 <service>
   <type>_smb._tcp</type>
   <port>445</port>
 </service>
 <service>
   <type>_device-info._tcp</type>
   <port>0</port>
   <txt-record>model=RackMac</txt-record>
 </service>
</service-group>

So I don't think that my system has been relying on NetBIOS at all.
> 
> I will check each new OS X update to see if this issue goes away.  Until
then, I just mount my shares via "Go- > 'Connect to
Server'".   Also note that you can re-enable NetBIOS support in
Catalina
(https://medium.com/@gobinathm/how-to-access-smb-printer-shares-in-macos-catalina-10-15-17ea91d2c10b).
I've not done nor tested that.
> 
> Hopefully a minor tweak to how you mount the SMB share will save you the
huge hassle of changing out tools.
> 
> Hope that helps.
> 
> Chris
Thanks for the suggestions.  I'll keep my eyes on the logs the next time I
do a big Lightroom import.

Cheers,

Andrew Reilly
E: areilly at bigpond.net.au
M: +61-409-824-272