TiDB 备份与恢复实践:用快照和日志建立可验证的 PITR 窗口

原作者:PingCAP 及 TiDB 文档贡献者。本文核对并整理自官方中文文档 TiDB 备份与恢复实践示例,核对日期为 2026-10-05。源页当前属于 v8.5 文档,示例假设 v8.5.8;文中的 2022 年时间点仅是原文教学场景,不是本次运行记录,也不是今天可直接发起的历史快照承诺。

假设业务运行在 AWS 上的 TiDB 生产集群里,团队同时提出两项要求:故障发生后,尽量只丢失事发前几分钟的数据;接到不定期审计请求时,能够另外提供一个数据库,查询过去一个月内某个时间点的数据。TiDB 的恢复到指定时间点能力(Point-in-time recovery,PITR)可以把定期快照与持续日志备份组合起来,支持这种恢复方式。

其中,快照提供某一时刻的完整基础数据,日志提供快照之后的数据变更。能否恢复到目标时刻,取决于二者构成的完整恢复链;看到日志任务为 NORMAL,并不等于任意目标时刻已经得到恢复验证。

TiDB PITR 时间线:从 5 月 14 日快照恢复,再回放连续日志直到 5 月 15 日 18 时;5 月 16 日快照晚于目标时间,不能作为此次恢复起点。保留窗口需要基础快照与完整日志链。
未完纪原创技术示意图;日期沿用官方教学例子,非实测结果。

部署与版本条件

PITR 需要 TiDB v6.2.0 或更新版本,并要求 BR 命令行工具与 TiDB 集群版本一致。原文以 v8.5.8 为例:尚未部署的集群先按 TiUP 部署文档 建立;已有集群低于 v6.2.0 时,需要先按相应升级文档完成升级。

原文列出的日志备份推荐配置如下。这是一组文档推荐配置,不是本次测出的最低资源需求;生产容量应按数据量、写入量和恢复目标另行规划。

组件 CPU 内存 磁盘类型 AWS 机型 数量
TiDB 8 核及以上 16 GB 及以上 SAS c5.2xlarge 2
PD 8 核及以上 16 GB 及以上 SSD c5.2xlarge 3
TiKV 8 核及以上 32 GB 及以上 SSD m5.2xlarge 3
BR CLI 8 核及以上 16 GB 及以上 SAS c5.2xlarge 1
监控 8 核及以上 16 GB 及以上 SAS c5.2xlarge 1

BR 在备份与恢复时都要访问 PD 和 TiKV,必须能连通所有需要的 PD、TiKV 节点。原文还要求 BR 所在服务器与 PD 所在服务器使用相同时区,避免对时间参数产生不同理解。本文示例保留明确的 +08:00 时区。

# 新安装与已有工具升级是两种情况,按需选择
tiup install br:v8.5.8
tiup update br:v8.5.8

本文后续把 tiup br 改写为显式的 tiup br:v8.5.8,这是版本锁定的编辑调整。实际集群若不是 v8.5.8,应成套使用与集群一致的工具及对应版本文档,不能只复制这个版本号。

配置 S3 存储与访问权限

备份开始前,准备 S3 桶、备份前缀和访问权限。原文使用 s3://tidb-pitr-bucket/backup-data 作为总路径,可新建桶,也可采用已批准用于备份的现有桶。S3 中的“目录”是对象键前缀,不是本地文件系统目录。

原文推荐 IAM 身份方式。让源集群的 TiKV 与 BR 具备备份需要的权限;让独立恢复集群及其 BR 仅具备读取备份的最小权限:

用途 原文列出的 S3 权限
备份端 TiKV 与 BR s3:ListBucket、s3:GetObject、s3:DeleteObject、s3:PutObject、s3:AbortMultipartUpload
恢复端 TiKV 与 BR s3:ListBucket、s3:GetObject

编写 IAM 策略时要区分桶级和对象级 Resource,并将范围限制到所需桶和备份前缀;如果另启用 KMS 等策略,也需要满足对应授权。不要把访问密钥硬编码进命令或放在共享稿件里。

快照与日志使用不同路径,避免混淆生命周期:

  • 每份快照:s3://tidb-pitr-bucket/backup-data/snapshot-<开始时间>,例如 snapshot-20220512000130。
  • 持续日志:s3://tidb-pitr-bucket/backup-data/log-backup/。

把业务要求转换成备份策略

原文的方案是持续运行日志备份,每隔两天在零点左右创建一份快照,并保留最近 30 天的恢复能力。自动化工具可以负责调度,但“保留 30 天”不能简单实现为删除所有对象年龄超过 30 天的文件:窗口最早端点可能仍依赖更早的基础快照,以及从那份快照开始的连续日志。

编辑补充:先确定需要支持的最早恢复时间,保留不晚于它的一份有效基础快照,再保留通往整个恢复窗口的日志链。快照间隔越长,从快照回放日志的工作可能越多;具体恢复耗时需要演练,本文不提供未经测量的恢复时间保证。

启动持续日志备份并检查进度

为避免误把恢复写回生产源集群,本文将原文统一使用的 PD_IP 拆分为 SOURCE_PD_ADDR 与 RESTORE_PD_ADDR。两者都应是管理员核对过、包含端口的 PD 地址;后者必须属于独立、适合恢复的目标集群。以下是 Bash 语法示例,不是在当前环境执行的脚本。

# SOURCE_PD_ADDR 由已审核配置提供,例如源集群的 PD 地址及 2379 端口
tiup br:v8.5.8 log start --task-name=pitr --pd="${SOURCE_PD_ADDR}" \
  --storage='s3://tidb-pitr-bucket/backup-data/log-backup'

tiup br:v8.5.8 log status --task-name=pitr --pd="${SOURCE_PD_ADDR}"

日志任务启动后,备份进程在 TiKV 集群运行,持续将变更写入 S3。状态输出中应关注任务名、状态、存储路径及 checkpoint[global]。原文的历史示例状态为 NORMAL,检查点为 2022-05-13 11:31:47.2 +0800,gap=4m53s;这只是原文输出,用来说明检查点相对当前进度存在间隔,并非本稿测量。

不能仅检查命令退出码或任务名称存在。需要持续观察检查点推进、延迟以及任务异常,同时确认真正想恢复的时刻已被备份覆盖。

定期创建全量快照

可用自动化运维工具(例如 cron)调度周期性快照。原文给出 2022 年 5 月 14 日和 16 日零点两次备份:

# 历史教学例子:时间、目录与 PD 地址必须按实际方案成套替换
tiup br:v8.5.8 backup full --pd="${SOURCE_PD_ADDR}" \
  --storage='s3://tidb-pitr-bucket/backup-data/snapshot-20220514000000' \
  --backupts='2022/05/14 00:00:00 +08:00'

tiup br:v8.5.8 backup full --pd="${SOURCE_PD_ADDR}" \
  --storage='s3://tidb-pitr-bucket/backup-data/snapshot-20220516000000' \
  --backupts='2022/05/16 00:00:00 +08:00'

这些时间不能在今天照抄后假定可用:指定历史快照时间需要满足实际集群保留历史版本的条件。应根据正在执行的备份计划选择受支持的时间点及独立的存储前缀,并核对备份完成状态。

恢复到审计要求的时间点

现在审计希望查询 2022-05-15 18:00:00 +0800 的数据。正确起点是 5 月 14 日快照,再回放它与目标时间之间的日志。5 月 16 日快照晚于目标,不能作为这次恢复的基础。

恢复目标必须是独立集群。 官方快照恢复指南要求空集群或没有冲突 schema/table 的集群;本例采用独立恢复环境以供审计。不要直接复用源 PD 地址,也不要对仍在提供业务写入的源集群执行下面的恢复。

# RESTORE_PD_ADDR 必须经过独立核对,指向恢复/审计集群
tiup br:v8.5.8 restore point --pd="${RESTORE_PD_ADDR}" \
  --storage='s3://tidb-pitr-bucket/backup-data/log-backup' \
  --full-backup-storage='s3://tidb-pitr-bucket/backup-data/snapshot-20220514000000' \
  --restored-ts '2022-05-15 18:00:00+0800'

原文展示的进度包含 Region Split/Scatter、SST 下载与导入、快照恢复、元数据文件恢复和 KV 日志恢复,并给出快照及日志 success summary。本文不复现填有 xxx 的示意日志为测试结果:本次没有运行 BR。实际执行后,应检查失败计数、恢复起止时间和目标库中的关键表,再用业务查询确认恢复到了要求的状态。

清理旧备份时保护恢复链

原文建议按周期清理过期备份,并举出“删除早于 2022-05-14 00:00:00 的快照”的例子。然而它紧随的语句是 rm s3://tidb-pitr-bucket/backup-data/snapshot-20220514000000:这既没有说明对象存储工具,也指向边界当天的快照,而不是“早于边界”的对象。

因此,本文不把这条语句作为可运行的清理命令。普通 shell 的 rm 不能按此写法可靠地完成 S3 前缀清理;若删掉 5 月 14 日这份基础快照,又截掉它之前的日志,可能失去一段原本需要保留的恢复能力。选择哪一个快照可删,应以经验证的恢复链为依据。

日志清理由 BR 的 log truncate 提供。原文的历史语法如下,仅用于解释选项,属于永久删除备份数据的操作:

# 历史示例;只有确认仍保留有效基础快照和完整恢复链后才可考虑执行
tiup br:v8.5.8 log truncate \
  --until='2022-05-14 00:00:00 +0800' \
  --storage='s3://tidb-pitr-bucket/backup-data/log-backup'

编辑修订的实际流程是:列出已成功完成的快照和日志覆盖范围,选定要保留的最早基础快照,验证它能够恢复到窗口内所需时间点,再审核允许删除的对象清单与日志截断时间。对象存储生命周期规则也要遵守同一链条,不能独立按对象年龄清除依赖。本文没有执行或自动化任何清理命令。

继续阅读与来源说明

版权所有:PingCAP 及 TiDB 文档贡献者。上游 docs-cn 许可证 为 CC BY-SA 3.0,本整理稿沿用该许可并保留署名,完整许可证附于本文末尾。© 2026 PingCAP. All Rights Reserved. 中文整理及编辑标注:未完纪,2026-10-05。本稿相对原文增加版本锁定、源/目标 PD 分离、备份链核查,并指出旧清理示例的不一致;原创示意图采用相同许可。

静态审查完成;未安装 BR、未访问 TiDB 或 S3、未发起备份/恢复/截断,未验证性能、RPO 或 RTO。未发现更多问题不等于没有漏洞或操作风险。

原文状态与恢复日志

以下完整保留原文历史示例;xxx 与 {TS} 是原文占位符,不是本次执行记录,也不能据此证明当前集群恢复成功。

tiup br log status --task-name=pitr --pd="${PD_IP}:2379"

● Total 1 Tasks.
> #1 <
    name: pitr
    status: ● NORMAL
    start: 2022-05-13 11:09:40.7 +0800
      end: 2035-01-01 00:00:00 +0800
    storage: s3://tidb-pitr-bucket/backup-data/log-backup
    speed(est.): 0.00 ops/s
checkpoint[global]: 2022-05-13 11:31:47.2 +0800; gap=4m53s
tiup br restore point --pd="${PD_IP}:2379" \
--storage='s3://tidb-pitr-bucket/backup-data/log-backup' \
--full-backup-storage='s3://tidb-pitr-bucket/backup-data/snapshot-20220514000000' \
--restored-ts '2022-05-15 18:00:00+0800'

Split&Scatter Region <--------------------------------------------------------------------------------------------------------------------------------------------------------> 100.00%
Download&Ingest SST <--------------------------------------------------------------------------------------------------------------------------------------------------------> 100.00%
Restore Pipeline <--------------------------------------------------------------------------------------------------------------------------------------------------------> 100.00%
[2022/05/29 18:15:39.132 +08:00] [INFO] [collector.go:69] ["Full Restore success summary"] [total-ranges=12] [ranges-succeed=xxx] [ranges-failed=0] [split-region=xxx.xxxµs] [restore-ranges=xxx] [total-take=xxx.xxxs] [restore-data-size(after-compressed)=xxx.xxx] [Size=xxxx] [BackupTS={TS}] [total-kv=xxx] [total-kv-size=xxx] [average-speed=xxx]
Restore Meta Files <--------------------------------------------------------------------------------------------------------------------------------------------------> 100.00%
Restore KV Files <----------------------------------------------------------------------------------------------------------------------------------------------------> 100.00%
[2022/05/29 18:15:39.325 +08:00] [INFO] [collector.go:69] ["restore log success summary"] [total-take=xxx.xx] [restore-from={TS}] [restore-to={TS}] [total-kv-count=xxx] [total-size=xxx]

版权与许可全文

以下保留本页涉及的来源材料或示例代码的版权、许可条件与免责声明;各自适用范围依原声明。中文翻译及编辑标注:未完纪,2026-10-05。

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