diff --git a/examples/deepscaler/run_deepscaler_disagg_v5p16.sh b/examples/deepscaler/run_deepscaler_disagg_v5p16.sh
index 7feb5b3d9..e0aedf5ba 100755
--- a/examples/deepscaler/run_deepscaler_disagg_v5p16.sh
+++ b/examples/deepscaler/run_deepscaler_disagg_v5p16.sh
@@ -32,9 +32,15 @@ warmup_ratio="${warmup_ratio:-0.1}"
 batch_size="${batch_size:-128}"
 mini_batch_size="${mini_batch_size:-128}"
 max_response_length="${max_response_length:-8192}"
+#TODO(b/510820709) - find the optimal mesh configuration
+total_tpus="${total_tpus:-8}"
+
 trainer_mesh="${trainer_mesh:-(4,1)}"
 rollout_mesh="${rollout_mesh:-(4,1)}"
 
+source "$(dirname "$0")/../tpu_utils.sh"
+validate_mesh_allocation "$total_tpus" "$trainer_mesh" "$rollout_mesh" "null" || exit 1
+
 checkpoint_dir="${checkpoint_dir:-gs://tunix/rl/checkpoints/01}"
 checkpoint_suffix="${checkpoint_suffix:-$(printf '%04d' "$((RANDOM % 10000))")}"
 if [[ -n "$checkpoint_dir" && "$checkpoint_dir" != "null" ]]; then
diff --git a/examples/deepswe/run_deepswe_disagg_v5p_32.sh b/examples/deepswe/run_deepswe_disagg_v5p_32.sh
index 5b73f063e..66fdb4a46 100755
--- a/examples/deepswe/run_deepswe_disagg_v5p_32.sh
+++ b/examples/deepswe/run_deepswe_disagg_v5p_32.sh
@@ -42,10 +42,15 @@ rollout_micro_batch_size="${rollout_micro_batch_size:-1}"
 
 num_generations="${num_generations:-2}"
 max_response_length="${max_response_length:-8192}"
-
+#TODO(b/510820709) - find the optimal mesh configuration.
+total_tpus="${total_tpus:-32}"
 trainer_mesh="${trainer_mesh:-(8,2)}"
 rollout_mesh="${rollout_mesh:-(2,8)}"
 
+
+source "$(dirname "$0")/../tpu_utils.sh"
+validate_mesh_allocation "$total_tpus" "$trainer_mesh" "$rollout_mesh" "null" || exit 1
+
 checkpoint_dir="${checkpoint_dir:-gs://tunix/rl/checkpoints/01}"
 checkpoint_suffix="${checkpoint_suffix:-$(printf '%04d' "$((RANDOM % 10000))")}"
 if [[ -n "$checkpoint_dir" && "$checkpoint_dir" != "null" ]]; then
diff --git a/examples/rl/grpo/gsm8k/run_gemma3_12b.sh b/examples/rl/grpo/gsm8k/run_gemma3_12b.sh
index f900f6c61..8eda350f9 100755
--- a/examples/rl/grpo/gsm8k/run_gemma3_12b.sh
+++ b/examples/rl/grpo/gsm8k/run_gemma3_12b.sh
@@ -54,8 +54,10 @@ python3 -m tunix.cli.grpo_main \
   actor_model_config.lora_config.module_path=".*q_einsum|.*kv_einsum|.*gate_proj|.*down_proj|.*up_proj|.*attn_vec_einsum" \
   actor_model_config.mesh.shape="(2,4)" \
   actor_model_config.mesh.axis_names="('fsdp','tp')" \
-  rollout_model_config.mesh.shape="(2,4)" \
-  rollout_model_config.mesh.axis_names="('fsdp','tp')" \
+  reference_model_config.mesh=null \
+  reference_model_config.same_mesh_as="actor" \
+  rollout_model_config.mesh=null \
+  rollout_model_config.same_mesh_as="actor" \
   tokenizer_config.tokenizer_path="gs://gemma-data/tokenizers/tokenizer_gemma3.model" \
   tokenizer_config.tokenizer_type="sentencepiece" \
   tokenizer_config.add_bos=false \
diff --git a/examples/rl/grpo/gsm8k/run_gemma3_1b.sh b/examples/rl/grpo/gsm8k/run_gemma3_1b.sh
index 0cad80455..a5ec7fd8a 100755
--- a/examples/rl/grpo/gsm8k/run_gemma3_1b.sh
+++ b/examples/rl/grpo/gsm8k/run_gemma3_1b.sh
@@ -54,8 +54,10 @@ python3 -m tunix.cli.grpo_main \
   actor_model_config.lora_config.module_path=".*q_einsum|.*kv_einsum|.*gate_proj|.*down_proj|.*up_proj|.*attn_vec_einsum" \
   actor_model_config.mesh.shape="(2,4)" \
   actor_model_config.mesh.axis_names="('fsdp','tp')" \
-  rollout_model_config.mesh.shape="(2,4)" \
-  rollout_model_config.mesh.axis_names="('fsdp','tp')" \
+  reference_model_config.mesh=null \
+  reference_model_config.same_mesh_as="actor" \
+  rollout_model_config.mesh=null \
+  rollout_model_config.same_mesh_as="actor" \
   tokenizer_config.tokenizer_path="gs://gemma-data/tokenizers/tokenizer_gemma3.model" \
   tokenizer_config.tokenizer_type="sentencepiece" \
   tokenizer_config.add_bos=false \
diff --git a/examples/rl/grpo/gsm8k/run_gemma3_4b.sh b/examples/rl/grpo/gsm8k/run_gemma3_4b.sh
index ef89e2b8a..b9e16495c 100755
--- a/examples/rl/grpo/gsm8k/run_gemma3_4b.sh
+++ b/examples/rl/grpo/gsm8k/run_gemma3_4b.sh
@@ -54,8 +54,10 @@ python3 -m tunix.cli.grpo_main \
   actor_model_config.lora_config.module_path=".*q_einsum|.*kv_einsum|.*gate_proj|.*down_proj|.*up_proj|.*attn_vec_einsum" \
   actor_model_config.mesh.shape="(2,4)" \
   actor_model_config.mesh.axis_names="('fsdp','tp')" \
-  rollout_model_config.mesh.shape="(2,4)" \
-  rollout_model_config.mesh.axis_names="('fsdp','tp')" \
+  reference_model_config.mesh=null \
+  reference_model_config.same_mesh_as="actor" \
+  rollout_model_config.mesh=null \
+  rollout_model_config.same_mesh_as="actor" \
   tokenizer_config.tokenizer_path="gs://gemma-data/tokenizers/tokenizer_gemma3.model" \
   tokenizer_config.tokenizer_type="sentencepiece" \
   tokenizer_config.add_bos=false \
diff --git a/examples/rl/grpo/gsm8k/run_gemma_7b.sh b/examples/rl/grpo/gsm8k/run_gemma_7b.sh
index 75f9f3f7a..8f6072ca0 100755
--- a/examples/rl/grpo/gsm8k/run_gemma_7b.sh
+++ b/examples/rl/grpo/gsm8k/run_gemma_7b.sh
@@ -55,8 +55,10 @@ python3 -m tunix.cli.grpo_main \
   actor_model_config.lora_config.module_path=".*q_einsum|.*kv_einsum|.*gate_proj|.*down_proj|.*up_proj|.*attn_vec_einsum" \
   actor_model_config.mesh.shape="(2,4)" \
   actor_model_config.mesh.axis_names="('fsdp','tp')" \
-  rollout_model_config.mesh.shape="(2,4)" \
-  rollout_model_config.mesh.axis_names="('fsdp','tp')" \
+  reference_model_config.mesh=null \
+  reference_model_config.same_mesh_as="actor" \
+  rollout_model_config.mesh=null \
+  rollout_model_config.same_mesh_as="actor" \
   tokenizer_config.tokenizer_path="/tmp/models/gemma-7b/models/google/gemma/flax/7b-it/2/tokenizer.model" \
   tokenizer_config.tokenizer_type="sentencepiece" \
   tokenizer_config.add_bos=false \
diff --git a/examples/rl/grpo/gsm8k/run_llama3.1_8b.sh b/examples/rl/grpo/gsm8k/run_llama3.1_8b.sh
index b91b04025..24ad05f33 100755
--- a/examples/rl/grpo/gsm8k/run_llama3.1_8b.sh
+++ b/examples/rl/grpo/gsm8k/run_llama3.1_8b.sh
@@ -53,8 +53,10 @@ python3 -m tunix.cli.grpo_main \
   actor_model_config.lora_config.module_path=".*q_proj|.*k_proj|.*v_proj|.*o_proj|.*gate_proj|.*down_proj|.*up_proj" \
   actor_model_config.mesh.shape="(2,4)" \
   actor_model_config.mesh.axis_names="('fsdp','tp')" \
-  rollout_model_config.mesh.shape="(2,4)" \
-  rollout_model_config.mesh.axis_names="('fsdp','tp')" \
+  reference_model_config.mesh=null \
+  reference_model_config.same_mesh_as="actor" \
+  rollout_model_config.mesh=null \
+  rollout_model_config.same_mesh_as="actor" \
   tokenizer_config.tokenizer_path="meta-llama/Llama-3.1-8B" \
   tokenizer_config.tokenizer_type="huggingface" \
   tokenizer_config.add_bos=false \
diff --git a/examples/rl/grpo/gsm8k/run_llama3.2_1b.sh b/examples/rl/grpo/gsm8k/run_llama3.2_1b.sh
index 63546bf0d..8035d458f 100755
--- a/examples/rl/grpo/gsm8k/run_llama3.2_1b.sh
+++ b/examples/rl/grpo/gsm8k/run_llama3.2_1b.sh
@@ -53,8 +53,10 @@ python3 -m tunix.cli.grpo_main \
   actor_model_config.lora_config.module_path=".*q_proj|.*k_proj|.*v_proj|.*o_proj|.*gate_proj|.*down_proj|.*up_proj" \
   actor_model_config.mesh.shape="(2,4)" \
   actor_model_config.mesh.axis_names="('fsdp','tp')" \
-  rollout_model_config.mesh.shape="(2,4)" \
-  rollout_model_config.mesh.axis_names="('fsdp','tp')" \
+  reference_model_config.mesh=null \
+  reference_model_config.same_mesh_as="actor" \
+  rollout_model_config.mesh=null \
+  rollout_model_config.same_mesh_as="actor" \
   tokenizer_config.tokenizer_path="meta-llama/Llama-3.2-1B" \
   tokenizer_config.tokenizer_type="huggingface" \
   tokenizer_config.add_bos=false \
diff --git a/examples/rl/grpo/gsm8k/run_qwen3.sh b/examples/rl/grpo/gsm8k/run_qwen3.sh
index 163767ed9..6490d97af 100755
--- a/examples/rl/grpo/gsm8k/run_qwen3.sh
+++ b/examples/rl/grpo/gsm8k/run_qwen3.sh
@@ -45,8 +45,10 @@ python3 -m tunix.cli.grpo_main \
   actor_model_config.lora_config.module_path=".*q_proj|.*k_proj|.*v_proj|.*o_proj|.*gate_proj|.*down_proj|.*up_proj" \
   actor_model_config.mesh.shape="(2,4)" \
   actor_model_config.mesh.axis_names="('fsdp','tp')" \
-  rollout_model_config.mesh.shape="(2,4)" \
-  rollout_model_config.mesh.axis_names="('fsdp','tp')" \
+  reference_model_config.mesh=null \
+  reference_model_config.same_mesh_as="actor" \
+  rollout_model_config.mesh=null \
+  rollout_model_config.same_mesh_as="actor" \
   tokenizer_config.tokenizer_path=Qwen/${model_name} \
   tokenizer_config.tokenizer_type=huggingface \
   tokenizer_config.add_bos=false \
diff --git a/examples/rl/grpo/gsm8k/run_qwen3_8b.sh b/examples/rl/grpo/gsm8k/run_qwen3_8b_disagg.sh
similarity index 97%
rename from examples/rl/grpo/gsm8k/run_qwen3_8b.sh
rename to examples/rl/grpo/gsm8k/run_qwen3_8b_disagg.sh
index dd5c2c173..4c2d5b2d2 100755
--- a/examples/rl/grpo/gsm8k/run_qwen3_8b.sh
+++ b/examples/rl/grpo/gsm8k/run_qwen3_8b_disagg.sh
@@ -41,10 +41,13 @@ rollout_micro_batch_size="${rollout_micro_batch_size:-8}"
 compute_logps_micro_batch_size="${compute_logps_micro_batch_size:-1}"
 
 num_generations="${num_generations:-4}"
-
+total_tpus="${total_tpus:-16}"
 train_mesh="${train_mesh:-(8,1)}"
 rollout_mesh="${rollout_mesh:-(1,8)}"
 
+source "$(dirname "$0")/../../../tpu_utils.sh"
+validate_mesh_allocation "$total_tpus" "$train_mesh" "$rollout_mesh" "null" || exit 1
+
 checkpoint_dir="${checkpoint_dir:-gs://tunix/rl/checkpoints/gsm8k/qwen3/01}"
 checkpoint_suffix="${checkpoint_suffix:-$(printf '%04d' "$((RANDOM % 10000))")}"
 if [[ -n "$checkpoint_dir" && "$checkpoint_dir" != "null" ]]; then
diff --git a/examples/rl/grpo/gsm8k/run_qwen3_8b_maxtext.sh b/examples/rl/grpo/gsm8k/run_qwen3_8b_disagg_maxtext.sh
similarity index 97%
rename from examples/rl/grpo/gsm8k/run_qwen3_8b_maxtext.sh
rename to examples/rl/grpo/gsm8k/run_qwen3_8b_disagg_maxtext.sh
index b094bd8bf..1cc85b569 100755
--- a/examples/rl/grpo/gsm8k/run_qwen3_8b_maxtext.sh
+++ b/examples/rl/grpo/gsm8k/run_qwen3_8b_disagg_maxtext.sh
@@ -39,10 +39,13 @@ rollout_micro_batch_size="${rollout_micro_batch_size:-8}"
 compute_logps_micro_batch_size="${compute_logps_micro_batch_size:-1}"
 
 num_generations="${num_generations:-4}"
-
+total_tpus="${total_tpus:-16}"
 train_mesh="${train_mesh:-(8,1)}"
 rollout_mesh="${rollout_mesh:-(1,8)}"
 
+source "$(dirname "$0")/../../../tpu_utils.sh"
+validate_mesh_allocation "$total_tpus" "$train_mesh" "$rollout_mesh" "null" || exit 1
+
 checkpoint_dir="${checkpoint_dir:-gs://tunix/rl/checkpoints/gsm8k/qwen3/01}"
 checkpoint_suffix="${checkpoint_suffix:-$(printf '%04d' "$((RANDOM % 10000))")}"
 if [[ -n "$checkpoint_dir" && "$checkpoint_dir" != "null" ]]; then
diff --git a/examples/rl/grpo/gsm8k/run_qwen3_simplereward.sh b/examples/rl/grpo/gsm8k/run_qwen3_simplereward.sh
index d655dfefd..b28f4aad3 100644
--- a/examples/rl/grpo/gsm8k/run_qwen3_simplereward.sh
+++ b/examples/rl/grpo/gsm8k/run_qwen3_simplereward.sh
@@ -54,8 +54,10 @@ python3 -m tunix.cli.grpo_main \
   actor_model_config.lora_config.module_path=".*q_proj|.*k_proj|.*v_proj|.*o_proj|.*gate_proj|.*down_proj|.*up_proj" \
   actor_model_config.mesh.shape="(2,4)" \
   actor_model_config.mesh.axis_names="('fsdp','tp')" \
-  rollout_model_config.mesh.shape="(2,4)" \
-  rollout_model_config.mesh.axis_names="('fsdp','tp')" \
+  reference_model_config.mesh=null \
+  reference_model_config.same_mesh_as="actor" \
+  rollout_model_config.mesh=null \
+  rollout_model_config.same_mesh_as="actor" \
   tokenizer_config.tokenizer_path=Qwen/${model_name} \
   tokenizer_config.tokenizer_type=huggingface \
   tokenizer_config.add_bos=false \
diff --git a/examples/rl/grpo/gsm8k/verl_compatible/run_llama3.2_1b.sh b/examples/rl/grpo/gsm8k/verl_compatible/run_llama3.2_1b.sh
index 59b9b2493..18a350149 100755
--- a/examples/rl/grpo/gsm8k/verl_compatible/run_llama3.2_1b.sh
+++ b/examples/rl/grpo/gsm8k/verl_compatible/run_llama3.2_1b.sh
@@ -51,8 +51,10 @@ python3 -m tunix.cli.grpo_main \
   actor_model_config.mesh.shape="(4,1)" \
   actor_model_config.mesh.axis_names="('fsdp','tp')" \
   actor_model_config.lora_config={} \
-  rollout_model_config.mesh.shape="(4,1)" \
-  rollout_model_config.mesh.axis_names="('fsdp','tp')" \
+  reference_model_config.mesh=null \
+  reference_model_config.same_mesh_as="actor" \
+  rollout_model_config.mesh=null \
+  rollout_model_config.same_mesh_as="actor" \
   tokenizer_config.tokenizer_path="meta-llama/Llama-3.2-1B-Instruct" \
   tokenizer_config.tokenizer_type="huggingface" \
   tokenizer_config.add_bos=false \
diff --git a/examples/tpu_utils.sh b/examples/tpu_utils.sh
new file mode 100644
index 000000000..8654c57e8
--- /dev/null
+++ b/examples/tpu_utils.sh
@@ -0,0 +1,71 @@
+# Copyright 2026 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+#!/bin/bash
+# tpu_utils.sh
+
+# Helper function: extracts dimensions from a mesh tuple and calculates the product
+calc_mesh_tpus() {
+  local input="$1"
+  if [[ -z "$input" || "$input" == "null" ]]; then
+    echo 0
+    return 0
+  fi
+  # Remove parens and spaces, then replace commas with spaces
+  local dims="${input//[() ]/}"
+  dims="${dims//,/ }"
+  local product=1
+  for d in $dims; do
+    if [[ -n "$d" ]]; then
+      product=$(( product * d ))
+    fi
+  done
+  echo $product
+}
+
+# Main validation function
+# Usage: validate_mesh_allocation <total_tpus> <trainer_mesh> <rollout_mesh> <reference_mesh>
+validate_mesh_allocation() {
+  if [[ $# -ne 4 ]]; then
+    echo "Error: validate_mesh_allocation requires exactly 4 arguments: <total_tpus> <trainer_mesh> <rollout_mesh> <reference_mesh>" >&2
+    echo "Got: $@" >&2
+    return 1
+  fi
+
+  local total_tpus="$1"
+  local trainer_mesh="$2"
+  local rollout_mesh="$3"
+  local reference_mesh="$4"
+
+  local trainer_tpus
+  local rollout_tpus
+  local reference_tpus
+  local required_tpus
+
+  trainer_tpus=$(calc_mesh_tpus "$trainer_mesh")
+  rollout_tpus=$(calc_mesh_tpus "$rollout_mesh")
+  reference_tpus=$(calc_mesh_tpus "$reference_mesh")
+  required_tpus=$(( trainer_tpus + rollout_tpus + reference_tpus ))
+
+  if (( required_tpus > total_tpus )); then
+    # Print errors to standard error (stderr) using >&2
+    echo "Error: Required TPUs ($required_tpus) exceeds total_tpus ($total_tpus)." >&2
+    echo "  Trainer needs: $trainer_tpus (mesh: $trainer_mesh)" >&2
+    echo "  Rollout needs: $rollout_tpus (mesh: $rollout_mesh)" >&2
+      echo "  Reference needs: $reference_tpus (mesh: $reference_mesh)" >&2
+    return 1 # Return failure so the caller can handle it
+  fi
+
+  return 0 # Return success
+}