本地搭建一个镜像站，可以大大提高更新系统和安装软件的速度，本文以Ubuntu为例，使用apt-mirror软件，搭建一个自己的镜像站，提高树莓派更新系统的速度。
一、条件
由于树莓派的镜像大小有70多G，所以在搭建前需要保证一个100G以上的硬盘空间，否则会由于硬盘容量太小而搭建失败。
同时首次同步镜像需要的时间比较长，所以时间由服务器的带宽决定。
二、开始搭建
首先安装apt-mirror软件：
sudo apt-get install apt-mirror
接着配置镜像站设置：
打开/etc/apt/mirror.list文件，进行如下配置：
############# config ################## # set base_path /mnt # # set mirror_path $base_path/mirror # set skel_path $base_path/skel # set var_path $base_path/var # set cleanscript $var_path/clean.sh # set defaultarch <running host architecture> # set postmirror_script $var_path/postmirror.sh # set run_postmirror 0 set nthreads 20 set _tilde 0 # ############# end config ############## deb http://mirrors.tuna.tsinghua.edu.cn/raspberrypi/ buster main ui deb http://mirrors.tuna.tsinghua.edu.cn/raspbian/raspbian/ buster main non-free contrib deb-src http://mirrors.tuna.tsinghua.edu.cn/raspbian/raspbian/ buster main non-free contrib #deb http://archive.ubuntu.com/ubuntu artful main restricted universe multiverse #deb http://archive.ubuntu.com/ubuntu artful-security main restricted universe multiverse #deb http://archive.ubuntu.com/ubuntu artful-updates main restricted universe multiverse #deb http://archive.ubuntu.com/ubuntu artful-proposed main restricted universe multiverse #deb http://archive.ubuntu.com/ubuntu artful-backports main restricted universe multiverse #deb-src http://archive.ubuntu.com/ubuntu artful main restricted universe multiverse #deb-src http://archive.ubuntu.com/ubuntu artful-security main restricted universe multiverse #deb-src http://archive.ubuntu.com/ubuntu artful-updates main restricted universe multiverse #deb-src http://archive.ubuntu.com/ubuntu artful-proposed main restricted universe multiverse #deb-src http://archive.ubuntu.com/ubuntu artful-backports main restricted universe multiverse clean http://mirrors.tuna.tsinghua.edu.cn/raspberrypi/
其中：
set base_path 表示要下载到哪个目录
然后开始同步镜像：
sudo apt-mirror
我使用的是华为云服务器同步，同步带宽大约在30Mbps。
大约用了7个小时才首次同步完，树莓派镜像的容量大约为80G。
最后为了能通过http访问到刚搭建的镜像站，需要在服务器上安装nginx服务器软件。
安装nginx :
sudo apt install nginx
建立连接，使得可以访问到镜像站：
sudo ln -s /mnt/mirror/ mirrors.tuna.tsinghua.edu.cn/raspbian/ /var/www/html/
这样镜像站就搭建完成了，可以在树莓派上将换源更新了。
三、开始使用
连接树莓派，修改镜像源配置。
编辑/etc/apt/sources.list文件。删除原文件所有内容，用以下内容取代：
deb http://121.36.81.4/raspbian/ buster main contrib non-free rpi
编辑此文件后，请使用sudo apt-get update命令，更新软件列表。
按理说应该可以了，但是有一些问题我用了一天也没有解决，这里记录下，等下次解决了才能修改。
目前存在的问题：
1.使用apt-mirror同步镜像源存在问题：
同步过程提示：
# apt-mirror Downloading 38 index files using 20 threads... Begin time: Fri May 1 19:47:35 2020 [20]... [19]... [18]... [17]... [16]... [15]... [14]... [13]... [12]... [11]... [10]... [9]... [8]... [7]... [6]... [5]... [4]... [3]... [2]... [1]... [0]... End time: Fri May 1 19:47:41 2020 Processing translation indexes: [T] Downloading 0 translation files using 0 threads... Begin time: Fri May 1 19:47:41 2020 [0]... End time: Fri May 1 19:47:41 2020 Processing DEP-11 indexes: [D] Downloading 0 dep11 files using 0 threads... Begin time: Fri May 1 19:47:41 2020 [0]... End time: Fri May 1 19:47:41 2020 apt-mirror: can't open index raspbian.raspberrypi.org/raspbian//dists/buster/main/binary-arm64/Packages in process_index at /usr/bin/apt-mirror line 800, <STREAM> chunk 1504. apt-mirror: can't open index raspbian.raspberrypi.org/raspbian//dists/buster/contrib/binary-arm64/Packages in process_index at /usr/bin/apt-mirror line 800, <STREAM> chunk 1504. apt-mirror: can't open index raspbian.raspberrypi.org/raspbian//dists/buster/non-free/binary-arm64/Packages in process_index at /usr/bin/apt-mirror line 800, <STREAM> chunk 1504. apt-mirror: can't open index raspbian.raspberrypi.org/raspbian//dists/buster/rpi/binary-arm64/Packages in process_index at /usr/bin/apt-mirror line 800, <STREAM> chunk 1504. Processing indexes: [P] 0 bytes will be downloaded into archive. Downloading 0 archive files using 0 threads... Begin time: Fri May 1 19:47:41 2020 [0]... End time: Fri May 1 19:47:41 2020 0 bytes in 0 files and 0 directories can be freed. Run /mnt/var/clean.sh for this purpose. Running the Post Mirror script ... (/mnt/var/postmirror.sh) /bin/sh: 0: Can't open /mnt/var/postmirror.sh Post Mirror script has completed. See above output for any possible errors.
出现了无法下载的情况，导致镜像源同步不完全。
2.可能由于镜像源同步 不完全的原因，造成树莓派更新出问题，如下：
$ sudo apt-get update 获取:1 http://121.36.81.4/raspbian/raspbian buster InRelease [15.0 kB] 忽略:2 http://121.36.81.4/raspbian/raspbian buster/main armhf Packages 命中:3 http://archive.raspberrypi.org/debian buster InRelease 忽略:4 http://121.36.81.4/raspbian/raspbian buster/contrib armhf Packages 忽略:5 http://121.36.81.4/raspbian/raspbian buster/non-free armhf Packages 忽略:6 http://121.36.81.4/raspbian/raspbian buster/rpi armhf Packages 忽略:2 http://121.36.81.4/raspbian/raspbian buster/main armhf Packages 忽略:4 http://121.36.81.4/raspbian/raspbian buster/contrib armhf Packages 忽略:5 http://121.36.81.4/raspbian/raspbian buster/non-free armhf Packages 忽略:6 http://121.36.81.4/raspbian/raspbian buster/rpi armhf Packages 错误:2 http://121.36.81.4/raspbian/raspbian buster/main armhf Packages 404 Not Found [IP: 121.36.81.4 80] 忽略:4 http://121.36.81.4/raspbian/raspbian buster/contrib armhf Packages 忽略:5 http://121.36.81.4/raspbian/raspbian buster/non-free armhf Packages 忽略:6 http://121.36.81.4/raspbian/raspbian buster/rpi armhf Packages 正在读取软件包列表... 完成 E: 无法下载 http://121.36.81.4/raspbian/raspbian/dists/buster/main/binary-armhf/Packages 404 Not Found [IP: 121.36.81.4 80] E: 部分索引文件下载失败。如果忽略它们，那将转而使用旧的索引文件。
你好，我想在树莓派4b上搭建此服务，但试了许多次，都失败了。
错误提示是什么？