qa/suites/nvmeof/thrasher: use 120 subsystems and 8 ns each

For tharsher test:
1. Run it on 120 subsystems with 8 namespaces each
2. Run FIO for 20 mins (instead of 15mins)
2. Run FIO for few randomly picked devices
    (using `--random_devices 200`)

Signed-off-by: Vallari Agrawal <vallari.agrawal@ibm.com>

qa/suites/nvmeof/thrash/gateway-initiator-setup/120-subsys-8-namespace.yaml

@@ -6,8 +6,8 @@ tasks:
       pool_name: mypool
       image_name_prefix: myimage
     gateway_config:
-      subsystems_count: 3
-      namespaces_count: 20 # each subsystem
+      subsystems_count: 120
+      namespaces_count: 8 # each subsystem
       cli_image: quay.io/ceph/nvmeof-cli:latest
 
 - cephadm.wait_for_service:

qa/suites/nvmeof/thrash/workloads/fio.yaml

@@ -1,11 +1,11 @@
 tasks:
 - workunit:
     no_coverage_and_limits: true
-    timeout: 30m
+    timeout: 60m
     clients:
       client.0:
-        - nvmeof/fio_test.sh
+        - nvmeof/fio_test.sh --random_devices 200
     env:
       RBD_POOL: mypool
       IOSTAT_INTERVAL: '10'
-      RUNTIME: '900'
+      RUNTIME: '1200'

qa/workunits/nvmeof/fio_test.sh

@@ -5,6 +5,7 @@ sudo yum -y install sysstat
 
 namespace_range_start=
 namespace_range_end=
+random_devices_count=
 rbd_iostat=false
 
 while [[ $# -gt 0 ]]; do
@@ -17,6 +18,10 @@ while [[ $# -gt 0 ]]; do
             namespace_range_end=$2
             shift 2
             ;;
+        --random_devices)
+            random_devices_count=$2
+            shift 2
+            ;;
         --rbd_iostat)
             rbd_iostat=true
             shift
@@ -37,6 +42,8 @@ all_drives_list=$(sudo nvme list --output-format=json |
 # run on first 3 namespaces here.
 if [ "$namespace_range_start" ] || [ "$namespace_range_end" ]; then
     selected_drives=$(echo "${all_drives_list[@]}" | sed -n "${namespace_range_start},${namespace_range_end}p")
+elif [ "$random_devices_count" ]; then 
+    selected_drives=$(echo "${all_drives_list[@]}" | shuf -n $random_devices_count)
 else
     selected_drives="${all_drives_list[@]}"
 fi