小带宽VPS服务器异地增量备份方案

异地存储直接本地挂载腾讯云对象存储。
	挂载路径：/www/cosfs/btbak-hk
	要备份的数据路径：/www/wwwroot
	备份软件：borg
	文档：https://borgbackup.readthedocs.io/en/stable/index.html
###备份保存方案：
1. 保存最近7天的每天备份
2. 保存最近4个周的每周备份
3. 保存最近6个月的每月备份

先初始化备份：
`borg init --encryption=none /www/cosfs/btbak-hk/btbak`

###自动备份脚本代码：
```shell
#!/bin/sh

# Setting this, so the repo does not need to be given on the commandline:
export BORG_REPO=/www/cosfs/btbak-hk/btbak

# See the section "Passphrase notes" for more infos.
# export BORG_PASSPHRASE='DragoneT1943ZEAC'

# some helpers and error handling:
info() { printf "\n%s %s\n\n" "$( date )" "$*" >&2; }
trap 'echo $( date ) Backup interrupted >&2; exit 2' INT TERM

info "Starting backup"

# Backup the most important directories into an archive named after
# the machine this script is currently running on:

borg create                         \
    --verbose                       \
    --filter AME                    \
    --list                          \
    --stats                         \
    --show-rc                       \
    --compression zstd,13           \
    ::'{hostname}-{now}'            \
    /www/wwwroot

backup_exit=$?

info "Pruning repository"

# Use the `prune` subcommand to maintain 7 daily, 4 weekly and 6 monthly
# archives of THIS machine. The '{hostname}-*' matching is very important to
# limit prune's operation to this machine's archives and not apply to
# other machines' archives also:

borg prune                          \
    --list                          \
    --glob-archives '{hostname}-*'  \
    --show-rc                       \
    --keep-daily    7               \
    --keep-weekly   4               \
    --keep-monthly  6

prune_exit=$?

# actually free repo disk space by compacting segments

info "Compacting repository"

borg compact

compact_exit=$?

# use highest exit code as global exit code
global_exit=$(( backup_exit > prune_exit ? backup_exit : prune_exit ))
global_exit=$(( compact_exit > global_exit ? compact_exit : global_exit ))

if [ ${global_exit} -eq 0 ]; then
    info "Backup, Prune, and Compact finished successfully"
elif [ ${global_exit} -eq 1 ]; then
    info "Backup, Prune, and/or Compact finished with warnings"
else
    info "Backup, Prune, and/or Compact finished with errors"
fi

exit ${global_exit}
```
####设置脚本每天执行一次即可。
- 其中，`--compression zstd,13`为压缩方式`zstd`，压缩级别`13`，数字范围`1-22`，越大压缩比越大，但CPU占用越大，速度越慢。

第一次备份是整站所有数据，从第二次备份开始，只增加变化的数据。

##效果：
###第一次备份：
10M小带宽，4.86G数据备份到腾讯云对象存储，
耗时3个半小时。
![截屏2023-12-24 09.18.42.png](https://dt27.cn/usr/uploads/2023/12/1932561243.png)
###第二次备份：
软件自动计算增量数据，需要传输的数据只有13.16MB，
备份时间29.84秒。
![截屏2023-12-24 09.22.38.png](https://dt27.cn/usr/uploads/2023/12/3005213487.png)