Imported from chaterm/terminal-skills (backup/snapshot/SKILL.md). Install upstream with npx skills add chaterm/terminal-skills --skill snapshot. Copyright stays with the author.

快照管理

概述

LVM 快照、文件系统快照、云快照管理技能。

LVM 快照

创建快照

# 查看逻辑卷
lvs
lvdisplay

# 创建快照
lvcreate -L 10G -s -n snap_data /dev/vg0/data

# 创建薄快照
lvcreate -s -n snap_data /dev/vg0/thin_data

# 查看快照
lvs -a
lvdisplay /dev/vg0/snap_data

挂载快照

# 挂载只读
mount -o ro /dev/vg0/snap_data /mnt/snapshot

# 挂载读写
mount /dev/vg0/snap_data /mnt/snapshot

恢复数据

# 从快照恢复
lvconvert --merge /dev/vg0/snap_data

# 恢复前需卸载原卷
umount /dev/vg0/data
lvconvert --merge /dev/vg0/snap_data
mount /dev/vg0/data /data

删除快照

# 卸载并删除
umount /mnt/snapshot
lvremove /dev/vg0/snap_data

Btrfs 快照

创建快照

# 创建只读快照
btrfs subvolume snapshot -r /data /snapshots/data_$(date +%Y%m%d)

# 创建可写快照
btrfs subvolume snapshot /data /snapshots/data_writable

# 查看子卷
btrfs subvolume list /

管理快照

# 删除快照
btrfs subvolume delete /snapshots/data_20240101

# 发送快照（备份）
btrfs send /snapshots/data_readonly | btrfs receive /backup/

# 增量发送
btrfs send -p /snapshots/old /snapshots/new | btrfs receive /backup/

ZFS 快照

创建快照

# 创建快照
zfs snapshot pool/dataset@snap_$(date +%Y%m%d)

# 递归创建
zfs snapshot -r pool/dataset@snap_name

# 查看快照
zfs list -t snapshot

管理快照

# 回滚
zfs rollback pool/dataset@snap_name

# 克隆
zfs clone pool/dataset@snap_name pool/clone_dataset

# 删除
zfs destroy pool/dataset@snap_name

# 发送/接收
zfs send pool/dataset@snap | zfs receive backup/dataset

云快照

AWS EBS

# 创建快照
aws ec2 create-snapshot \
    --volume-id vol-1234567890abcdef0 \
    --description "Backup $(date +%Y%m%d)"

# 查看快照
aws ec2 describe-snapshots --owner-ids self

# 从快照创建卷
aws ec2 create-volume \
    --snapshot-id snap-1234567890abcdef0 \
    --availability-zone us-east-1a

# 删除快照
aws ec2 delete-snapshot --snapshot-id snap-1234567890abcdef0

阿里云

# 创建快照
aliyun ecs CreateSnapshot --DiskId d-xxx --SnapshotName backup

# 查看快照
aliyun ecs DescribeSnapshots

# 删除快照
aliyun ecs DeleteSnapshot --SnapshotId s-xxx

常见场景

场景 1：数据库一致性快照

#!/bin/bash
# MySQL + LVM 快照
mysql -e "FLUSH TABLES WITH READ LOCK;"
lvcreate -L 10G -s -n db_snap /dev/vg0/mysql_data
mysql -e "UNLOCK TABLES;"

# 备份快照
mount -o ro /dev/vg0/db_snap /mnt/snap
tar -czvf /backup/mysql_$(date +%Y%m%d).tar.gz /mnt/snap
umount /mnt/snap
lvremove -f /dev/vg0/db_snap

场景 2：自动快照脚本

#!/bin/bash
# Btrfs 自动快照
SNAP_DIR="/snapshots"
MAX_SNAPS=7

# 创建快照
btrfs subvolume snapshot -r /data ${SNAP_DIR}/data_$(date +%Y%m%d_%H%M)

# 清理旧快照
ls -1d ${SNAP_DIR}/data_* | head -n -${MAX_SNAPS} | xargs -r btrfs subvolume delete

场景 3：快照前后钩子

#!/bin/bash
# 快照前
systemctl stop application
sync

# 创建快照
lvcreate -L 5G -s -n app_snap /dev/vg0/app_data

# 快照后
systemctl start application

故障排查

# LVM 快照状态
lvs -a -o +snap_percent

# Btrfs 空间
btrfs filesystem df /
btrfs filesystem usage /

# ZFS 空间
zfs list -o space