AI Infrastructure·8 min read·

Deploying High-Throughput vLLM Inference Clusters on Dedicated GPU VPS

Optimize PagedAttention, continuous batching, and chunked prefill for serving open weights models at sub-20ms first-token latency in production.

NB

Netbay Infrastructure Team

Netbay Engineering

On this page

Serving large language models (LLMs) in production is notoriously resource-intensive. Traditional model serving frameworks suffer from severe GPU memory fragmentation caused by dynamic sequence lengths. In naive HuggingFace or PyTorch serving setups, up to 70% of high-bandwidth GPU memory (HBM) is wasted on reserved, unallocated Key-Value (KV) cache memory.

vLLM solves this memory bottleneck through PagedAttention, an algorithm inspired by virtual memory paging in operating systems. By dividing the KV cache into fixed-size physical blocks, vLLM achieves near-zero memory waste, unlocking continuous batching and delivering up to 4x higher token throughput on dedicated Linux servers.

Core Architectural Primitives in vLLM

To maximize serving efficiency for open-weights models like Llama 3.3 and DeepSeek V3:

  1. PagedAttention Memory Manager: Allocates KV cache memory on-demand in 16-token non-contiguous blocks, allowing dynamic sequence expansion without pre-allocation.
  2. Continuous Batching Scheduler: Merges incoming requests into running iteration batches at each token generation step, keeping GPU tensor cores saturated.
  3. Chunked Prefill: Splices large prompt processing jobs into smaller chunks, preventing long prompts from causing latency spikes for existing streaming sessions.
vLLM High-Throughput Inference Engine Architecture Client Requests OpenAI Compatible API Streaming SSE / JSON Port 8000 vLLM Engine Coordinator Continuous Batch Scheduler PagedAttention Block Manager Chunked Prefill Enabled Zero Memory Fragmentation GPU 0 (Tensor Parallel 1) Paged KV Cache Blocks (16 tokens) GPU 1 (Tensor Parallel 2) Paged KV Cache Blocks (16 tokens) Serving Latency Benchmarks (70B Model) Time to First Token (TTFT): 18.4ms | Generation Speed: 84 tokens/sec Sustains 120 concurrent streaming users without tail latency spikes

Production Deployment with Systemd and Docker

Below is an automated production configuration running vLLM in a hardened Docker container with NVIDIA container toolkit integration:

yaml
# /srv/vllm/docker-compose.yaml
version: '3.8'

services:
  vllm:
    image: vllm/vllm-openai:latest
    container_name: vllm-prod
    restart: unless-stopped
    runtime: nvidia
    environment:
      - HUGGING_FACE_HUB_TOKEN=hf_prod_token_here
      - VLLM_ATTENTION_BACKEND=FLASH_ATTN
    ports:
      - "127.0.0.1:8000:8000"
    volumes:
      - /srv/models:/root/.cache/huggingface
    command: >
      --model meta-llama/Llama-3.3-70B-Instruct
      --tensor-parallel-size 2
      --gpu-memory-utilization 0.92
      --max-model-len 8192
      --enable-chunked-prefill
      --max-num-batched-tokens 2048
      --disable-log-requests
    deploy:
      resources:
        reservations:
          devices:
            - driver: nvidia
              count: all
              capabilities: [gpu]

Systemd Health Monitor Service

To ensure automatic recovery, wrap the instance in a systemd watchdog:

ini
# /etc/systemd/system/vllm.service
[Unit]
Description=vLLM High-Throughput Inference Service
After=docker.service
Requires=docker.service

[Service]
Type=simple
WorkingDirectory=/srv/vllm
ExecStart=/usr/bin/docker compose up
ExecStop=/usr/bin/docker compose down
Restart=always
RestartSec=10

[Install]
WantedBy=multi-user.target
Expand
GPU Hardware and Accelerated Inference
Dedicated GPU inference cluster

Video Deep Dive on vLLM Production Serving

Watch this architectural session explaining continuous batching and KV cache memory optimization:

High-Performance LLM Serving with vLLM
YouTube

Adopting vLLM slashes GPU infrastructure costs while providing ultra-responsive streaming responses for production AI applications.

Deploy high-capacity GPU VPS instances with enterprise NVMe storage and dedicated PCIe bandwidth on Netbay Cloud at netbayhosts.in.

Keep reading

Follow along on a real VPS

Deploy Linux in under 60 seconds

These guides are written against Ubuntu, Debian, and RHEL-family images — the same ones on NetBay.

Deploy an instance