# FDSP + QLoRA

## Background

Using FSDP with QLoRA is essential for **fine-tuning larger (70b+ parameter) LLMs on consumer GPUs.**  For example, you can use FSDP + QLoRA to train a 70b model on two 24GB GPUs[^1].

Below, we describe how to use this feature in Axolotl.

## Usage

To enable `QLoRA` with `FSDP`, you need to perform the following steps:

> ![Tip]
> See the [example config](#example-config) file in addition to reading these instructions.

1. Set `adapter: qlora` in your axolotl config file.
2. Enable FSDP in your axolotl config, as [described here](https://github.com/OpenAccess-AI-Collective/axolotl?tab=readme-ov-file#fsdp).
3. Use one of the supported model types: `llama`, `mistral` or `mixtral`.

## Example Config

[examples/llama-2/qlora-fsdp.yml](../examples/llama-2/qlora-fsdp.yml) contains an example of how to enable QLoRA + FSDP in axolotl.

## References

- [PR #1378](https://github.com/OpenAccess-AI-Collective/axolotl/pull/1378) enabling QLoRA in FSDP in Axolotl.
- [Blog Post](https://www.answer.ai/posts/2024-03-06-fsdp-qlora.html) from the [Answer.AI](https://www.answer.ai/) team describing the work that enabled QLoRA in FSDP.
- Related HuggingFace PRs Enabling FDSP + QLoRA:
    - Accelerate [PR#2544](https://github.com/huggingface/accelerate/pull/2544 )
    - Transformers [PR#29587](https://github.com/huggingface/transformers/pull/29587)
    - TRL [PR#1416](https://github.com/huggingface/trl/pull/1416)
    - PEFT [PR#1550](https://github.com/huggingface/peft/pull/1550)




[^1]: This was enabled by [this work](https://www.answer.ai/posts/2024-03-06-fsdp-qlora.html) from the Answer.AI team.