Você está ativando um "recurso" do systemd conhecido; Além disso, o sistema pode estar tentando montar o compartilhamento SAMBA remoto antes que a rede esteja operacional.
Modifique seu fstab para adicionar às opções de montagem ,noauto,x-systemd.automount,_netdev
//192.168.1.1/FRITZ.NAS/WD-1600BEVExternal-01/share /srv/nas cifs credentials=/home/rlommers/.smbcredentials,rw,uid=rlommers,gid=rlommers,noauto,x-systemd.automount,_netdev 0 0
Para a explicação, corrigida para a nova sintaxe por mim - Truque bonito do dia: montagem automática de compartilhamentos remotos
If you have remote drives – cifs, nfs, whatever – in /etc/fstab with typical options, then you’ll probably find that the system will sit there and wait for the network to come up on boot, then mount them, before boot completes. That’s not terrible, but it’s not awesome either.
...
to make it super awesome, add two options:noauto
andx-systemd.automount
.
Then what happens is the share gets mounted as soon as something tries to access it…but not before.
So boot runs as fast as possible, and as soon as you actually try to access the share, it gets mounted. Thanks, systemd!
Também do Arch Wiki para explicar esse recurso - fstab
Automount with systemd
Remote filesystem
The same applies to remote filesystem mounts. If you want them to be mounted only upon access, you will need to use the noauto,x-systemd.automount parameters. In addition, you can use the x-systemd.device-timeout= option to specify how long systemd should wait for the filesystem to show up. Also, the _netdev option ensures systemd understands that the mount is network dependent and order it after the network is online.
noauto,x-systemd.automount,x-systemd.device-timeout=30,_netdev
Aviso : teste o fstab
antes de reinicializar com sudo mount -o remount -a
e sudo mount -o rw,remount /srv/nas
, pois um fstab
errôneo pode causar problemas na inicialização.
Veja também, relacionado, CIFS perdendo aleatoriamente a conexão com o compartilhamento do Windows