Scylla is a fault-tolerant system. A cluster can be available even when more than one node is down.
Verify the status of the cluster using nodetool status command. A node with status
DN is down and needs to be replaced.
Datacenter: DC1 Status=Up/Down State=Normal/Leaving/Joining/Moving -- Address Load Tokens Owns (effective) Host ID Rack UN 192.168.1.201 112.82 KB 256 32.7% 8d5ed9f4-7764-4dbd-bad8-43fddce94b7c B1 DN 192.168.1.202 91.11 KB 256 32.9% 125ed9f4-7777-1dbn-mac8-43fddce9123e B1 DN 192.168.1.203 124.42 KB 256 32.6% 675ed9f4-6564-6dbd-can8-43fddce952gy B1
Login to one of the nodes in the cluster with (UN) status, collect the following info from the node:
cat /etc/scylla/scylla.yaml | grep cluster_name
cat /etc/scylla/scylla.yaml | grep seeds:
cat /etc/scylla/scylla.yaml | grep endpoint_snitch
Scylla version -
Depend on the Replication Factor (RF)
If the number of failed nodes is smaller than your keyspaces RF, you still have at least one available replica with your data, and you can use Replace a Dead Node procedure.
If the number of failed nodes is equal or larger than your keyspaces RF, then some of the data is lost, and you need to retrieve it from backup. Use the Replace a Dead Node procedure and restore the data from backup.