add validation to prevent 8bit lora finetuning on H100s (#1827)

src/axolotl/utils/config/models/input/v0_4_1/__init__.py

@@ -1267,6 +1267,19 @@ class AxolotlConfigWCapabilities(AxolotlInputConfig):
 
         return data
 
+    @model_validator(mode="before")
+    @classmethod
+    def check_hopper_8bit_lora(cls, data):
+        is_sm_90: bool = (
+            data["capabilities"]
+            and data["capabilities"].get("compute_capability") == "sm_90"
+        )
+        if data.get("adapter") and data.get("load_in_8bit") and is_sm_90:
+            # see https://github.com/bitsandbytes-foundation/bitsandbytes/issues/538#issuecomment-2262945464
+            raise ValueError("8-bit LoRA is not supported on Hopper GPUs")
+
+        return data
+
     @model_validator(mode="before")
     @classmethod
     def check_fsdp_deepspeed(cls, data):