知道为什么我需要"yum clean dbcache metadata"经常这样做吗？我使用的是centos6.6，它有epel repo。它经常无法从镜像获取包并出现 404 错误，直到我再次清理 yum。以下是日志的一部分。
Trying other mirror.
http://mirrors.syringanetworks.net/fedora-epel/6/x86_64/repodata/3a5d63c8e27b2a5b5bf046c71ec05e3710df642c3e13f6e6354bd2b613f3c7e7-updateinfo.xml.gz: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
Trying other mirror.
http://mirror.sfo12.us.leaseweb.net/epel/6/x86_64/repodata/3a5d63c8e27b2a5b5bf046c71ec05e3710df642c3e13f6e6354bd2b613f3c7e7-updateinfo.xml.gz: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
Trying other mirror.
http://mirrors.cat.pdx.edu/epel/6/x86_64/repodata/3a5d63c8e27b2a5b5bf046c71ec05e3710df642c3e13f6e6354bd2b613f3c7e7-updateinfo.xml.gz: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
Trying other mirror.
http://mirrors.tummy.com/pub/fedora.redhat.com/epel/6/x86_64/repodata/3a5d63c8e27b2a5b5bf046c71ec05e3710df642c3e13f6e6354bd2b613f3c7e7-updateinfo.xml.gz: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
Trying other mirror.
http://mirrors.kernel.org/fedora-epel/6/x86_64/repodata/3a5d63c8e27b2a5b5bf046c71ec05e3710df642c3e13f6e6354bd2b613f3c7e7-updateinfo.xml.gz: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 404 Not Found"
Trying other mirror.
这是重新抛光的输出
# yum repolist
Loaded plugins: fastestmirror, presto, security
Loading mirror speeds from cached hostfile
* base: mirror.solarvps.com
* epel: mirror.symnds.com
* extras: mirror.metrocast.net
* updates: mirror.es.its.nyu.edu
repo id repo name status
base CentOS-6 - Base 6,518
epel Extra Packages for Enterprise Linux 6 - x86_64 11,745
extras CentOS-6 - Extras 38
updates CentOS-6 - Updates 1,370
repolist: 19,671
更新：我使用厨师食谱来安装。https://github.com/chef-cookbooks/yum-epel ..我没有看到任何用于安装存储库的特殊方法。
/var/log/yum.log （显示我今天安装的插件，清理 yum 后）
Jul 07 20:42:05 Installed: wget-1.12-5.el6_6.1.x86_64
Jul 23 17:17:12 Updated: nginx-filesystem-1.0.15-12.el6.noarch
Jul 23 17:17:12 Updated: nginx-1.0.15-12.el6.x86_64
Jul 30 21:25:43 Installed: yum-plugin-security-1.1.30-30.el6.noarch
/etc/yum.conf
# This file was generated by Chef
# Do NOT modify this file by hand.
[main]
cachedir=/var/cache/yum/$basearch/$releasever
debuglevel=2
distroverpkg=centos-release
exactarch=1
gpgcheck=1
installonly_limit=3
keepcache=0
logfile=/var/log/yum.log
obsoletes=1
plugins=1
/etc/yum.repos.d/epel.repo
# This file was generated by Chef
# Do NOT modify this file by hand.
[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
enabled=1
failovermethod=priority
gpgcheck=1
gpgkey=https://dl.fedoraproject.org/pub/epel/RPM-GPG-KEY-EPEL-6
mirrorlist=https://mirrors.fedoraproject.org/metalink?repo=epel-6&arch=$basearch
sslverify=true