今天deepvps在一个 CentOS VPS 上升级系统时遇到一个问题，yum 报错：
# yum update
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
Traceback (most recent call last):
File “/usr/bin/yum”, line 29, in ?
yummain.user_main(sys.argv[1:], exit_code=True)
File “/usr/share/yum-cli/yummain.py”, line 229, in user_main
errcode = main(args)
File “/usr/share/yum-cli/yummain.py”, line 104, in main
result, resultmsgs = base.doCommands()
File “/usr/share/yum-cli/cli.py”, line 339, in doCommands
self._getTs(needTsRemove)
File “/usr/lib/python2.4/site-packages/yum/depsolve.py”, line 101, in _getTs
self._getTsInfo(remove_only)
File “/usr/lib/python2.4/site-packages/yum/depsolve.py”, line 112, in _getTsInfo
pkgSack = self.pkgSack
File “/usr/lib/python2.4/site-packages/yum/__init__.py”, line 591, in
pkgSack = property(fget=lambda self: self._getSacks(),
File “/usr/lib/python2.4/site-packages/yum/__init__.py”, line 434, in _getSacks
self.repos.populateSack(which=repos)
File “/usr/lib/python2.4/site-packages/yum/repos.py”, line 223, in populateSack
self.doSetup()
File “/usr/lib/python2.4/site-packages/yum/repos.py”, line 71, in doSetup
self.ayum.plugins.run(‘postreposetup’)
File “/usr/lib/python2.4/site-packages/yum/plugins.py”, line 176, in run
func(conduitcls(self, self.base, conf, **kwargs))
File “/usr/lib/yum-plugins/fastestmirror.py”, line 181, in postreposetup_hook
all_urls = FastestMirror(all_urls).get_mirrorlist()
File “/usr/lib/yum-plugins/fastestmirror.py”, line 333, in get_mirrorlist
self._poll_mirrors()
File “/usr/lib/yum-plugins/fastestmirror.py”, line 376, in _poll_mirrors
pollThread.start()
File “/usr/lib/python2.4/threading.py”, line 416, in start
_start_new_thread(self.__bootstrap, ())
thread.error: can’t start new thread
yum 在启动 fastestmirror 插件时出错，是 yum 的一个 bug（http://yum.baseurl.org/ticket/70）。如果停掉 mysqld，yum 一切工作正常。临时解决办法是 yum update 时禁止启动 fastestmirror 插件。
yum –disableplugin=fastestmirror update
