It has been a long time since something has frustrated me this much.

Have tried two different approaches, with the same result.

Media on a Windows 2012 R2 server, rock solid, never have a single problem with it.

Plex running on Linux. Have tried Ubuntu 16.04, and am now trying the official Plex Docker image running under VMware Photon OS.

This is how I mount the media shares (where .smbcredentials is a file containing the credentials for connecting to the shares)

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cat >> /etc/fstab <<EOF
//fileserver.fqdn/Movies$ /plexmedia/Movies cifs credentials=/root/.smbcredentials,uid=1000,gid=1000,file_mode=0664,dir_mode=0774 0 0
//fileserver.fqdn/TV$ /plexmedia/TV cifs credentials=/root/.smbcredentials,uid=1000,gid=1000,file_mode=0664,dir_mode=0774 0 0
EOF

mkdir -p /plexmedia/Movies
mkdir -p /plexmedia/TV
chown -R 1000:1000 /plexmedia

mount -a

Symptoms: after random amounts of time (hours, a few days), Plex loses the ability to see the media folders. The web interface still works fine, can browse everything, but trying to play something back leads to the endless rotating "throbber". No errors except for timeout.

Clients: iPhone, iPad (latest, both on iOS 10 latest), Amazon Fire TV (the non-4K one), web, macOS (the dmg downloaded from plex website).

If I SSH to the server and try an ls on the /plexmedia/Movies or /plexmedia/TV directories I get very weird behaviour. This evening, I could happily ls the Movies folder, but ls on the TV folder would hang the VM (I'd have to disconnect and open a new SSH session). The plex docker image was hung so badly that docker kill plex wouldn't kill it, so I had to stop the docker service. Reboots always fix the problem, but it always re-occurs.

I've tried dozens of minor tweaks to how I mount the drives, and it doesn't seem to make a difference.

Please help!!! INCREDIBLY frustrated.