PostgreSQL容器磁盘I/O监控与优化指南

iostat -d -k 2  # BusyBox可用基础命令
iostat -dx 2    # 完整版功能，BusyBox不支持

docker exec -it test-postgresql bash -c "iostat -d -k 2"

Device             tps    kB_read/s    kB_wrtn/s    kB_dscd/s    kB_read    kB_wrtn    kB_dscd
vda               5.67        32.45       128.76         0.00    1048576    4194304          0

# Debian/Ubuntu系容器
docker exec -it test-postgresql bash -c "apt update && apt install -y sysstat"

# Alpine系容器
docker exec -it test-postgresql bash -c "apk add sysstat"

iostat -dx 2  # 显示扩展统计
iostat -c 2   # 查看CPU与I/O等待关系

# 查找容器使用的实际设备
device=$(docker inspect test-postgresql | grep -A5 "DeviceName" | grep "Source" | cut -d'"' -f4)

# 监控该设备
iostat -dx $device 2

kB_wrtn/s呈现规律性波动 → 检查点活动
持续高kB_wrtn/s → 事务量过大

ALTER SYSTEM SET wal_buffers = '16MB';  -- 默认4MB，大事务可增加
ALTER SYSTEM SET checkpoint_completion_target = 0.9;  -- 平滑检查点
ALTER SYSTEM SET max_wal_size = '2GB';  -- 根据负载调整

ALTER SYSTEM SET shared_buffers = '4GB';  -- 通常设为内存25%
ALTER SYSTEM SET effective_cache_size = '12GB';  -- 可用内存的50-75%

-- 对于SSD存储
ALTER SYSTEM SET random_page_cost = 1.1;
ALTER SYSTEM SET seq_page_cost = 1.0;

SELECT query, calls, total_time, shared_blks_read
FROM pg_stat_statements
ORDER BY shared_blks_read DESC
LIMIT 10;

/var/lib/postgresql/data → 主数据（高性能设备）
/pg_wal → 单独高速设备（可选）
/pg_log → 可放在普通设备

ALTER SYSTEM SET checkpoint_timeout = '30min';
SELECT pg_reload_conf();

ALTER SYSTEM SET max_connections = 100;

ALTER SYSTEM SET work_mem = '8MB';

# docker-compose-monitoring.yml
version: "3"
services:
  prometheus:
    image: prom/prometheus
    ports: ["9090:9090"]

  grafana:
    image: grafana/grafana
    ports: ["3000:3000"]

  node-exporter:
    image: prom/node-exporter
    volumes: ["/proc:/host/proc", "/sys:/host/sys"]

{
  "storage-driver": "overlay2",
  "storage-opts": ["overlay2.override_kernel_check=true"]
}

docker run -d \
  --mount type=volume,dst=/var/lib/postgresql/data,volume-opt=type=xfs \
  postgres:14

docker run -d \
  --memory="8g" \
  --memory-swap="12g" \
  --cpu-shares=1024 \
  --blkio-weight=500 \
  postgres:14