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