今天升级Mariadb，下载速度很慢，因为用的Mariadb官方源，由于墙的关系？导致下载很慢，才几KB/S，我是电信50M光钎宽带啊，而且还出现超时的现象，换成中国电信天翼云镜像源，下载速度达到2.8M/S，爽歪歪。

Total download size: 141 M
Downloading packages:
Delta RPMs disabled because /usr/bin/applydeltarpm not installed.
MariaDB-10.1.22-centos7-x86_64 FAILED                                                                                      ] 1.5 kB/s | 526 kB  25:43:27 ETA 
http://yum.mariadb.org/10.1/centos7-amd64/rpms/MariaDB-10.1.22-centos7-x86_64-common.rpm: [Errno 12] Timeout on http://yum.mariadb.org/10.1/centos7-amd64/rpms/MariaDB-10.1.22-centos7-x86_64-common.rpm: (28, 'Operation too slow. Less than 1000 bytes/sec transferred the last 30 seconds')
Trying other mirror.
MariaDB-10.1.22-centos7-x86_64 FAILED                                                                                      ]   48 B/s | 794 kB 841:51:57 ETA 
http://yum.mariadb.org/10.1/centos7-amd64/rpms/MariaDB-10.1.22-centos7-x86_64-client.rpm: [Errno 12] Timeout on http://yum.mariadb.org/10.1/centos7-amd64/rpms/MariaDB-10.1.22-centos7-x86_64-client.rpm: (28, 'Operation too slow. Less than 1000 bytes/sec transferred the last 30 seconds')
Trying other mirror.
MariaDB-10.1.22-centos7-x86_64 FAILED                                                                                      ]  0.0 B/s | 321 kB  --:--:-- ETA 
http://yum.mariadb.org/10.1/centos7-amd64/rpms/MariaDB-10.1.22-centos7-x86_64-server.rpm: [Errno 12] Timeout on http://yum.mariadb.org/10.1/centos7-amd64/rpms/MariaDB-10.1.22-centos7-x86_64-server.rpm: (28, 'Operation too slow. Less than 1000 bytes/sec transferred the last 30 seconds')
Trying other mirror.
(1/3): MariaDB-10.1.22-centos7-x86_64-common.rpm                                                                                      | 123 kB  00:00:43     
MariaDB-10.1.22-centos7-x86_64 FAILED                                                                                    ]  1.9 B/s | 920 kB 21532:16:48 ETA 
http://yum.mariadb.org/10.1/centos7-amd64/rpms/MariaDB-10.1.22-centos7-x86_64-client.rpm: [Errno 12] Timeout on http://yum.mariadb.org/10.1/centos7-amd64/rpms/MariaDB-10.1.22-centos7-x86_64-client.rpm: (28, 'Operation too slow. Less than 1000 bytes/sec transferred the last 30 seconds')

把官方源换成中国电信天翼云镜像源

官方源：下载几KB/S
root@localhost ~]# vi /etc/yum.repos.d/MariaDB.repo 

[mariadb]
name = MariaDB
baseurl = http://yum.mariadb.org/10.1/centos7-amd64
gpgkey=https://yum.mariadb.org/RPM-GPG-KEY-MariaDB
gpgcheck=1

换成中国电信天翼云的源，下载速度有很大提升。2.8M/S
[root@localhost ~]# cat /etc/yum.repos.d/MariaDB.repo 
[mariadb]
name = MariaDB
baseurl = http://mirrors.ctyun.cn/MariaDB/yum/10.1/centos7-amd64
gpgkey=http://mirrors.ctyun.cn/MariaDB/yum/RPM-GPG-KEY-MariaDB
gpgcheck=1

运行以下命令生成缓存
yum clean all
yum makecache

换源以后的效果：

Total size: 217 M
Total download size: 140 M
Downloading packages:
Delta RPMs disabled because /usr/bin/applydeltarpm not installed.
(1/2): MariaDB-10.1.22-centos7-x86_64-client.rpm                                                                                      |  39 MB  00:00:19     
(2/2): MariaDB-10.1.22-centos7-x86_64-server.rpm                                                                                      | 101 MB  00:00:49     
-------------------------------------------------------------------------------------------------------------------------------------------------------------
Total                                                                                                                        2.8 MB/s | 140 MB  00:00:49