diff --git a/sdcm/nemesis.py b/sdcm/nemesis.py
index b65ef6bed0..9130fb57e5 100644
--- a/sdcm/nemesis.py
+++ b/sdcm/nemesis.py
@@ -2109,6 +2109,10 @@ def disrupt_truncate_large_partition(self):
         it's used to cover one improvement of compaction.
         The increase frequency of checking abortion is very useful for truncate.
         """
+        if (SkipPerIssues(issues="https://github.com/scylladb/scylladb/issues/20356",
+                          params=self.tester.params)
+                and self.tester.params.get("use_zero_nodes")):
+            raise UnsupportedNemesis("Unsupported nemesis due to scylladb/scylladb#20356")
         ks_name = 'ks_truncate_large_partition'
         table = 'test_table'
         stress_cmd = "scylla-bench -workload=sequential -mode=write -replication-factor=3 -partition-count=10 " + \
diff --git a/test-cases/longevity/longevity-multi-dc-rack-aware-with-znode-in-diff_dc.yaml b/test-cases/longevity/longevity-multi-dc-rack-aware-with-znode-in-diff_dc.yaml
index 5e5d726115..99007eadf2 100644
--- a/test-cases/longevity/longevity-multi-dc-rack-aware-with-znode-in-diff_dc.yaml
+++ b/test-cases/longevity/longevity-multi-dc-rack-aware-with-znode-in-diff_dc.yaml
@@ -7,7 +7,7 @@ stress_cmd: ["cassandra-stress write cl=LOCAL_QUORUM duration=720m -schema 'repl
              "cassandra-stress read  cl=LOCAL_QUORUM duration=720m -schema 'replication(strategy=NetworkTopologyStrategy,replication_factor=3,eu-northscylla_node_north=0) compaction(strategy=SizeTieredCompactionStrategy)' -port jmx=6868 -mode cql3 native -rate threads=40 -pop 'dist=uniform(1..20971520)' -col 'n=FIXED(10) size=FIXED(512)' -log interval=5 -errors retries=50",
              ]
 
-n_db_nodes: '3 3 0'
+n_db_nodes: '4 4 0'
 n_loaders: '1 1'
 n_monitor_nodes: 1
 n_db_zero_token_nodes: '0 1 1'