LLMOps — কী আলাদা
এই পাঠে যা শিখবেন
- LLMOps vs classical MLOps — key differences
- Foundation model vs fine-tune vs RAG decision
- Vector DB landscape
- Bangla LLM-specific challenges
১ · কেন আলাদা
Classical ML: train custom model, deploy, monitor. LLM-এ অনেক assumption ভাঙে।
২ · ৭টি core difference
- Non-determinism: temperature, top-p — same prompt different output.
- Prompt as artifact: code-like, version controlled, tested.
- Foundation model dependency: rarely train from scratch; fine-tune or use API.
- RAG infrastructure: vector DB, retrieval, context management.
- Token cost: input + output tokens, model-tier pricing.
- Hallucinations: confidently wrong; classical metric inadequate.
- Streaming: token-by-token return; latency definition shifted.
৩ · Build vs buy
- API (OpenAI, Anthropic, Cohere):
- Pros: zero infra, latest model, fast.
- Cons: per-token cost, data privacy, vendor lock.
- Self-host open model (LLaMA, Mistral, Qwen):
- Pros: data control, customizable, eventually cheaper at scale.
- Cons: GPU cost, ops complexity, behind frontier.
- Fine-tune:
- Pros: domain-specific quality, smaller model possible.
- Cons: training cost, drift management.
৪ · RAG (Retrieval Augmented Generation)
LLM-এর knowledge cut-off + hallucinations issue. RAG = retrieve relevant context → LLM answer.
- Document ingestion → chunk → embed → vector DB.
- Query: embed query → vector search → top-k chunks.
- Prompt: "Given context: [...], answer: ..."।
৫ · Vector DB landscape
- FAISS (Meta): in-memory library; fast; no persistence built-in.
- pgvector (Postgres): embedded SQL extension; familiar; scalable.
- Qdrant: Rust-built, fast, REST API.
- Weaviate: GraphQL, schema-aware, hybrid search.
- Pinecone: SaaS, easiest, pricey.
- Chroma: simple, dev-friendly.
- Milvus: Cloud-native, K8s-friendly, large scale.
৬ · Simple RAG example
import openai
import psycopg2
from psycopg2.extras import execute_values
# 1. Ingest documents
def ingest(docs: list[str], conn):
for doc in docs:
emb = openai.embeddings.create(
input=doc, model="text-embedding-3-small"
).data[0].embedding
conn.execute(
"INSERT INTO docs (text, embedding) VALUES (%s, %s)",
(doc, emb),
)
# 2. Retrieve top-k
def retrieve(query: str, k: int = 5, conn) -> list[str]:
emb = openai.embeddings.create(
input=query, model="text-embedding-3-small"
).data[0].embedding
rows = conn.execute(
"""SELECT text FROM docs
ORDER BY embedding <=> %s::vector
LIMIT %s""",
(emb, k),
).fetchall()
return [r[0] for r in rows]
# 3. Generate
def answer(query: str, conn) -> str:
chunks = retrieve(query, conn=conn)
context = "\n".join(chunks)
prompt = f"""Context:
{context}
Question: {query}
Answer:"""
resp = openai.chat.completions.create(
model="gpt-4o-mini",
messages=[{"role": "user", "content": prompt}],
)
return resp.choices[0].message.content
৭ · Hallucinations
LLM confidently wrong answer. Classical metric adequately capture না।
- Detection: factuality check (knowledge graph), self-consistency, retrieval grounding.
- Mitigation: RAG, low temperature, instruct model "say I don't know".
- Eval: human review, LLM-as-judge (Lesson 30).
৮ · Bangla LLM specifics
- Tokenization — Bangla character-rich; many model token-inefficient (300% more tokens).
- Models: BanglaT5, BanglaGPT, BanglaBERT, mBART, BanglaLLaMA.
- Eval scarce — Bangla benchmarks limited.
- Cultural context — Western model often miss.
ভাবনার প্রশ্ন
প্র ০১"Foundation model vs fine-tune vs RAG — কখন কোনটা?"
Choice depends task + data + budget.
Foundation model (out-of-box):
- Pros: zero data needed, fast iterate.
- Cons: generic; specialized task moderate quality.
- Use: prototyping, simple tasks (summarize, translate).
RAG:
- Pros: knowledge grounding, no training, easy update knowledge.
- Cons: retrieval quality dependent, latency added.
- Use: question-answering with proprietary documents.
Fine-tune:
- Pros: domain-specific quality, faster inference (smaller model).
- Cons: training data needed, retrain cost.
- Use: classification, structured output, style adaptation.
Decision tree:
- "Knowledge facts (changing)" → RAG.
- "Style/format adaptation" → fine-tune.
- "Generic task" → foundation.
- "Complex domain" → fine-tune + RAG.
BD example — Bangla customer support:
- Knowledge: company FAQ → RAG.
- Tone: friendly Bangla → fine-tune.
- Both combined: best result.
মূল উপলব্ধি: RAG-first usually. Fine-tune for style/format. Foundation for prototype. Combined production stack-এ different layers.
প্র ০২"In-house LLM hosting vs API — Bangladesh fintech-এ?"
Strategic decision — privacy, cost, latency.
API (OpenAI, Anthropic):
- Pros: best quality, no infra, fast iterate.
- Cons: data privacy (financial), per-token cost, latency to US.
Self-host:
- Pros: data control, fixed cost at scale, on-prem possible.
- Cons: GPU expensive, ops, lower model quality.
Hybrid:
- Sensitive — self-host (anonymized data API).
- Non-sensitive — API.
Bangladesh Bank ICT:
- Customer data abroad — restrictive.
- Self-host or anonymize before API.
Cost crossover:
- OpenAI GPT-4o: $5/1M input + $15/1M output tokens.
- 1M conversations/day × 1K tokens = 1B tokens/day = $5K-15K/day.
- Self-host: ~$5K/month cluster fixed.
- Crossover at ~50K conversations/day.
BD reality:
- Most BD startups API (cost manageable at low volume).
- Banks/fintech moving self-host for compliance + scale.
- Hybrid common compromise.
মূল উপলব্ধি: Volume + privacy → self-host; agility + low-volume → API. Hybrid practical for most production.
প্র ০৩"Bangla LLM tokenization inefficiency কতটা painful?"
Bangla character-rich; many models trained primarily on English.
Tokenization tax:
- English: ~0.75 tokens/word.
- Bangla on English-tuned tokenizer: ~3-5 tokens/word.
- Translation: 1 Bangla word = 4× cost vs English.
Models with better Bangla:
- GPT-4o — improved multilingual; still 2-3× English.
- Claude 3 — comparable.
- Gemini — Google's Bangla focus.
- BanglaGPT, BanglaT5 — Bangla-native tokenizer; 1× rate.
Cost impact:
- $1000/month English → $3000-5000/month Bangla.
- Significant for scale.
Mitigation:
- Translate to English (lossy).
- Bangla-native model (lower quality).
- Custom tokenizer + fine-tune.
- Hybrid: structured fields English; user input Bangla.
BD platform reality:
- Customer support chatbot — Bangla-heavy, cost surprise often.
- Budget projection English-rate → 3× actual.
মূল উপলব্ধি: Bangla token cost asymmetry critical for BD ops planning. Realistic estimate at start. Bangla-native model evaluate seriously.
প্র ০৪"Hallucination — production-grade mitigation strategy?"
Hallucination single biggest LLM production risk.
Sources:
- Knowledge gap — model doesn't know, fabricates.
- Reasoning failure — confident wrong logic.
- Prompt ambiguity — model assumes.
Mitigation layers:
(১) Retrieval grounding:
- "Answer from context only".
- Citations forced — answer cite source.
- Mostly RAG-based.
(২) Low temperature:
- Temperature 0.0-0.2 for fact-based.
- Reduces creativity, increases consistency.
(৩) Self-verification:
- "Check your answer for accuracy" follow-up prompt.
- "I don't know" allowed in instruction.
(৪) Output guardrails:
- NeMo Guardrails, LlamaGuard.
- Citation verification — generated facts vs source.
(৫) Confidence scores:
- Multi-sample agreement = confidence.
- Low confidence → escalate human.
(৬) Human-in-loop:
- Critical decision — review queue.
- Spot-check sample.
BD context — financial advice:
- Hallucinated rates / regulations dangerous.
- Strict RAG grounding.
- Disclaimers.
- Low-confidence → human.
মূল উপলব্ধি: Hallucination = layered defense. RAG + temperature + guardrails + human review. Single technique insufficient. Risk-tier task accordingly.
অনুশীলন
- Mini RAG: Local pgvector + OpenAI embedding + GPT-4o-mini — 10 docs ingest, query.
Postgres pgvector enable. Sample text ingest. Query similar retrieve.
- Compare: Same prompt 5 times — output variation observe.
Temperature 0.7 visible variation; 0.0 stable. Determinism trade-off.
- চিন্তা: Bangla customer support chatbot architecture design — vendor + RAG + guardrails.
- OpenAI GPT-4o + custom Bangla prompt template.
- RAG: Bangla FAQ pgvector.
- Guardrails: PII filter, max length, profanity check.
- Confidence scoring → human escalation.
- Logging: full conversation analytics.