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I found several posts on this, but none of them work.

When I do yum update, I get the error thread.error: can't start new thread; full stacktrace follows:

[root@ripper234 ~]# 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/", line 309, in user_main
    errcode = main(args)
  File "/usr/share/yum-cli/", line 178, in main
    result, resultmsgs = base.doCommands()
  File "/usr/share/yum-cli/", line 345, in doCommands
  File "/usr/lib/python2.4/site-packages/yum/", line 101, in _getTs
  File "/usr/lib/python2.4/site-packages/yum/", line 112, in _getTsInfo
    pkgSack = self.pkgSack
  File "/usr/lib/python2.4/site-packages/yum/", line 661, in <lambda>
    pkgSack = property(fget=lambda self: self._getSacks(),
  File "/usr/lib/python2.4/site-packages/yum/", line 501, in _getSacks
  File "/usr/lib/python2.4/site-packages/yum/", line 232, in populateSack
  File "/usr/lib/python2.4/site-packages/yum/", line 79, in doSetup'postreposetup')
  File "/usr/lib/python2.4/site-packages/yum/", line 179, in run
    func(conduitcls(self, self.base, conf, **kwargs))
  File "/usr/lib/yum-plugins/", line 181, in postreposetup_hook
    all_urls = FastestMirror(all_urls).get_mirrorlist()
  File "/usr/lib/yum-plugins/", line 333, in get_mirrorlist
  File "/usr/lib/yum-plugins/", line 376, in _poll_mirrors
  File "/usr/lib/python2.4/", line 416, in start
    _start_new_thread(self.__bootstrap, ())
thread.error: can't start new thread

I've already tried yum clean, that didn't help.

My OS is Centos 5.5.

share|improve this question
Looks pretty much like python problem. Why don't you post this to yum bugtracker? – alex Dec 6 '10 at 19:57
I've gotten this error when I ran out of memory on a small (64M) VM. – barrycarter Mar 26 '11 at 15:42
@barrycarter - me too. – ripper234 Mar 27 '11 at 22:09

2 Answers 2

This is mostly an issue with yum in CentOS 5.5+ versions and is caused by the fastestmirror plugin. One way to bypass is to use yum update --disableplugin=fastestmirror.

The best method to use rather than disabling the plugin completely is to reduce the number of threads. To this just edit the /etc/yum/pluginconf.d/fastestmirror.conf file and change the value maxthreads=xx to a lower value.

My default values were 15 and was giving an error with 150MB+ free RAM; I changed it to 5 and no more troubles.

share|improve this answer

You could try to disable fastestmirror plugin and check if after that change yum will be working properly. To disable it do: edit /etc/yum/pluginconf.d/fastestmirror.conf and change enabled = 1 to 0 or just remove plugin package: yum remove yum-fastestmirror or yum remove yum-plugin-fastestmirror.

share|improve this answer
is that a typo? didn't you mean remove instead of install? – freeforall tousez Nov 16 '14 at 15:03
Yup. It was typo. Fixed now. – pbm Nov 17 '14 at 13:38

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