Lost data after restarting ES


We have 6 indexes on 5 nodes each shard on a node with no replic.

I had a red health on ES today , which appears to be that one shard of one index unassigned due to full disk space,
After emptying the server from dummy data. I restarted the node that should have the unassigned node , but it didn't work at All.

Then restarted the whole nodes and had 5 shards unassigned.

I have on my configurations
cluster.routing.allocation.disable_allocation: true

After that we changed the configurations to
cluster.routing.allocation.disable_new_allocation: true
cluster.routing.allocation.disable_allocation: true
cluster.routing.allocation.allow_primary: true

and restarted the whole node.
After that the whole shards become unassigned and we discovered that the data on the hard disk is also removed.

I want to make sure, what we did wrong so we wont that again.

How can I recover unassigned shard for future ? is it by restart ?