test(backup): Measure read/write latency during back up

* 50% reads and 50% writes.
* Compaction enabled.
* 75%-85% CPU utilization
* Expect up to 6-7ms P99 read latencies.
* Expect not more than 10ms read latency during backup

configurations/manager/100GB_dataset.yaml

@@ -5,7 +5,7 @@ prepare_write_cmd: [ "cassandra-stress write cl=ALL n=26214400 -schema 'replicat
                      "cassandra-stress write cl=ALL n=26214400 -schema 'replication(strategy=NetworkTopologyStrategy,replication_factor=3)' -mode cql3 native  -rate threads=500 -col 'size=FIXED(1024) n=FIXED(1)' -pop seq=52428801..78643200",
                      "cassandra-stress write cl=ALL n=26214400 -schema 'replication(strategy=NetworkTopologyStrategy,replication_factor=3)' -mode cql3 native  -rate threads=500 -col 'size=FIXED(1024) n=FIXED(1)' -pop seq=78643201..104857600" ]
 
-stress_cmd: [ "cassandra-stress mixed cl=QUORUM duration=10m -schema 'replication(strategy=NetworkTopologyStrategy,replication_factor=3)' -mode cql3 native  -rate 'threads=100 fixed=5000/s' -col 'size=FIXED(1024) n=FIXED(1)'" ]
+stress_cmd: "cassandra-stress mixed cl=QUORUM duration=10m -schema 'replication(strategy=NetworkTopologyStrategy,replication_factor=3)' -mode cql3 native  -rate 'threads=100 fixed=5000/s' -col 'size=FIXED(1024) n=FIXED(1)'"
 
 instance_type_db: 'i4i.4xlarge'
 instance_type_loader: 'c6i.xlarge'