LND Security best practices? Disaster recovery? Can anyone share a knowledge how to

_ secure LND node 

_ backup node with all Channels

I think only a seed will not be sufficient. 
What is your plan B in case of disaster? How to do an  Emergency restore, migration to other server, or set up high availability solution?
thanks
You can secure an LND node in the same way how you would secure any host on the internet. You can for example use ufw to set up a firewall. You could also have a physical firewall in front of you node. Also a big step towards security would be to run no other software on the node. 

As for backups it is a little bit more tricky. The seedwords will not include the state of all of your channels. With the current channel design you cannot restore an old backup. As an old channel state would - following the protocol - allow your channel partners to claim all bitcoins in that channel. However you can use a distributed file system or a distributed data base to store your channel state. If configured properly writing to the file system or database will certainly be slower as all calls have to be synchronized and blocking. 
Also you could at least have a raid system that helps if a disk crashes.

Generally you can shutdown your lightning node and migrate it to another computer by copying the database. As mentioned again it is tricky as you really have to make sure that you don't migrate old state. I have a video showing this for c-lightning. The process for lnd should be similar.