Service

LLM Dataset Preparation & Structuring Service

Transform cleaned enterprise data into fine-tuning-ready JSONL and vector-ready Parquet datasets. Structured for Axolotl, LLaMA-Factory, Unsloth, and every major RAG framework — entirely on-premise.

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JSONL
Fine-tuning output format
Parquet
RAG & vector DB format
10+
Fine-tuning frameworks supported
0
Manual formatting steps
Overview

What Is LLM Dataset Preparation?

LLM dataset preparation is the process of taking cleaned, validated data and structuring it into the precise formats that fine-tuning frameworks and retrieval-augmented generation (RAG) pipelines require. It is the bridge between raw data cleaning and the actual training or inference infrastructure.

Even perfectly clean data in the wrong format will fail at training time. Fine-tuning frameworks are strict about schema: field names, message role conventions, token count limits per example, and instruction/response pairing format all need to be exactly right. A single malformed record can corrupt an entire training run.

VaultData's dataset preparation service handles schema design, format conversion, train/validation/test splitting, token budget management, and vector embedding preparation — all running inside your infrastructure with zero external dependencies.

Output Formats

Every Format Your Training Stack Needs

FINE-TUNING

JSONL — Instruction Tuning

The standard format for supervised fine-tuning across all major frameworks. We support every major schema:

  • ChatML — system/user/assistant message array (OpenAI-compatible)
  • Alpaca — instruction / input / output triplets
  • ShareGPT — multi-turn conversation format
  • Custom — any schema your model requires
{ "messages": [
{ "role": "user", "content": "..." },
{ "role": "assistant", "content": "..." }
] }
RAG / VECTOR DB

Parquet — Vector Pipeline

Columnar storage optimized for large-scale embedding generation and vector database ingestion:

  • Chunked text with configurable overlap and stride
  • Metadata columns — source, timestamp, category, tags
  • Pre-computed embeddings column (optional)
  • Direct ingest into Pinecone, Weaviate, Milvus, Qdrant
# Parquet schema
text: string
source: string
chunk_id: int32
token_count: int16
embedding: list<float32>
Capabilities

What the Preparation Pipeline Does

01

Schema Design & Mapping

We map your cleaned source data fields to the target fine-tuning schema. For instruction datasets, we design system prompts and user/assistant pairing logic based on your task type (summarization, classification, Q&A, code generation). For RAG, we define chunk boundaries, overlap strategy, and metadata schema.

02

Token Budget Management

Every record is tokenized using the target model's actual tokenizer (e.g., tiktoken for GPT-family, sentencepiece for LLaMA-family). Records exceeding the context window limit are split, truncated, or flagged based on your configured strategy. Token distribution histograms are included in the output report.

03

Train / Validation / Test Split

Stratified splits are generated to ensure balanced representation of topics, sources, and response lengths across all three partitions. Default split is 90/5/5; custom ratios are supported. Contamination checking prevents any near-duplicate from appearing in both train and eval sets.

04

Chunking for RAG

For retrieval pipelines, documents are chunked using a semantic boundary strategy (paragraph-aware, sentence-aware, or fixed-token sliding window with configurable overlap). Chunk size is calibrated to your embedding model's optimal input length (typically 256–512 tokens for most BERT-class encoders).

05

Quality Scoring & Filtering

After structuring, each record receives a composite quality score based on instruction/response length ratio, response informativeness, and coherence. Low-scoring records are flagged for review before export, preventing them from polluting your training distribution.

06

Framework Validation

The final dataset is validated by loading a sample through the target framework's data loader (Axolotl, LLaMA-Factory, Hugging Face datasets) inside your environment. Zero-error validation is confirmed before handoff — no post-processing surprises at training time.

Compatibility

Supported Training Frameworks & Vector Databases

Fine-Tuning Frameworks

Output validated for direct loading by:

  • Axolotl
  • LLaMA-Factory
  • Unsloth
  • Hugging Face TRL (SFTTrainer)
  • DeepSpeed + FSDP
  • OpenAI fine-tuning API

Vector Databases

Parquet output tested with:

  • Pinecone
  • Weaviate
  • Milvus
  • Qdrant
  • pgvector (PostgreSQL)
  • ChromaDB (local)

Base Models Supported

Schema and tokenizer support for:

  • LLaMA 3 / Mistral / Mixtral
  • Qwen 2.5 / Phi-3 / Gemma
  • GPT-4o fine-tuning API
  • Command R / DBRX
  • Custom / private models

Related Services & Resources

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