Guide - Linux 服务器自动备份 (Rsync + Cron)

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#!/bin/bash

# ==========================================
# 1. 全局配置区域 (All Configurations)
# ==========================================

# --- 路径配置 ---
# [注意] SRC_DIR 末尾必须带斜杠 / (表示同步目录内的内容，而不是目录本身)
SRC_DIR="/path/to/local/source/"

REMOTE_USER="your_remote_user"
REMOTE_HOST="remote.backup-server.com" # 或者填写 IP: 192.168.x.x
REMOTE_BASE="/mnt/backup_drive/user_backups"

# [注意] REMOTE_DEST_DIR 末尾建议带斜杠 / (保持语义清晰)
REMOTE_DEST_DIR="${REMOTE_BASE}/workspace_mirror/"

# 历史目录 (基于日期)
TODAY=$(date +%Y-%m-%d)
BACKUP_HISTORY_DIR="${REMOTE_BASE}/workspace_history/${TODAY}"

# --- 日志与锁文件配置 ---
LOG_DIR="/home/your_username/scripts/sync/logs"
DAILY_LOG="${LOG_DIR}/${TODAY}.log"
SKIPPED_LOG="${LOG_DIR}/skipped.log"
LOCK_FILE="/tmp/rsync_backup.lock"
HOSTNAME=$(hostname)

# --- Slack 报警配置 ---
# 请替换为您自己的 Webhook URL
SLACK_URL="https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX"
# 设定截止日期 (格式: YYYYMMDD)。例如：想观察到年底为止
OBSERVATION_END_DATE=20251231
# ==========================================
# 2. 初始化与锁 (Init & Lock)
# ==========================================

# 必须先创建日志目录
mkdir -p "$LOG_DIR"

# 防止重入锁 (Singleton Pattern)
exec 9>"$LOCK_FILE"
if ! flock -n 9 ; then
    echo "$(date): Backup already running. Skipped." >> "$SKIPPED_LOG"

    # [新增] 锁冲突报警：如果上一次任务卡死超过24小时，必须通知
    MSG="{\"text\":\"⚠️ *Backup SKIPPED (Locked)* \nHostname: ${HOSTNAME}\nTime: $(date)\nReason: Previous backup is still running (Zombie process?)\"}"
    curl -s -X POST -H 'Content-type: application/json' --data "$MSG" "$SLACK_URL" || true

    exit 200
fi
# ==========================================
# 3. 安全检查 (Safety Checks)
# ==========================================

# 源目录是否存在
# 如果 workspace 挂载掉线，rsync 会视为空目录从而删除远程文件，必须拦截
if [[ ! -d "$SRC_DIR" ]]; then
    echo "CRITICAL ERROR at $(date): SRC_DIR ($SRC_DIR) does not exist! Aborting." >> "$DAILY_LOG"

    # 发送致命错误报警
    MSG="{\"text\":\"🚨 *Backup CRITICAL!* \nHostname: ${HOSTNAME}\nError: Source Directory Missing! Check Mounts.\"}"
    curl -s -X POST -H 'Content-type: application/json' --data "$MSG" "$SLACK_URL" || true

    exit 1
fi

# 源目录必须以 / 结尾
if [[ "$SRC_DIR" != */ ]]; then
    echo "CRITICAL ERROR at $(date): SRC_DIR ($SRC_DIR) missing trailing slash '/'. Aborting." >> "$DAILY_LOG"
    exit 1
fi

# 目标目录必须以 / 结尾
if [[ "$REMOTE_DEST_DIR" != */ ]]; then
    echo "CRITICAL ERROR at $(date): REMOTE_DEST_DIR ($REMOTE_DEST_DIR) missing trailing slash '/'. Aborting." >> "$DAILY_LOG"
    exit 1
fi

# ==========================================
# 4. 执行业务逻辑 (Execution)
# ==========================================

echo "Start backup at $(date)" >> "$DAILY_LOG" # 改为追加，保留上面的报错信息的可能性

# ionice -c3: 磁盘空闲才运行
ionice -c3 rsync -avh \
  -e "ssh -o ConnectTimeout=10 -o ServerAliveInterval=60 -o ServerAliveCountMax=3" \
  --delete \
  --backup \
  --backup-dir="$BACKUP_HISTORY_DIR" \
  "$SRC_DIR" \
  "${REMOTE_USER}@${REMOTE_HOST}:${REMOTE_DEST_DIR}" >> "$DAILY_LOG" 2>&1

EXIT_CODE=$?

echo "End backup at $(date) with exit code $EXIT_CODE" >> "$DAILY_LOG"

# ==========================================
# 5. 清理旧日志 (Cleanup)
# ==========================================

# 只删除 "202x-xx-xx.log" 格式的文件
find "$LOG_DIR" -name "????-??-??.log" -type f -mtime +30 -delete

# ==========================================
# 6. Slack 报警 (Slack Alerts)
# ==========================================

# --- A. 失败报警 ---
if [ $EXIT_CODE -ne 0 ]; then
    MSG="{\"text\":\"🚨 *Backup FAILED!* \nHostname: ${HOSTNAME}\nTime: $(date)\nError Code: $EXIT_CODE\nLog: $DAILY_LOG\"}"
    # [优化] 增加 || echo ... 防止 curl 失败导致静默
    curl -s -X POST -H 'Content-type: application/json' --data "$MSG" "$SLACK_URL" || echo "WARNING: Slack notification failed" >> "$DAILY_LOG"
fi

# --- B. 观察期成功通知 ---
CURRENT_DATE_NUM=$(date +%Y%m%d)
if [ $EXIT_CODE -eq 0 ] && [ "$CURRENT_DATE_NUM" -le "$OBSERVATION_END_DATE" ]; then
    MSG="{\"text\":\"✅ *Backup SUCCESS* (Observation Period)\nHostname: ${HOSTNAME}\nTime: $(date)\n\nℹ️ Valid until $OBSERVATION_END_DATE\"}"
    curl -s -X POST -H 'Content-type: application/json' --data "$MSG" "$SLACK_URL" || echo "WARNING: Slack notification failed" >> "$DAILY_LOG"
fi