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।