To follow up the first installment , it turns outthat enabling the source repositories has a side effect that I didn'tthink about at the time: it no longer looks in the default repositories.

(This is a general thing in yumdownloader : any time you specify arepository explicitly, it disables all the default ones. This makesme grumpy. While you can argue that this makes a sort of sense, itis not how yum itself behaves when you enable repositories, and yumdownloader uses the exact same command line

Now that we know how NFS is unreliable , we cansee what can go wrong when you attempt to do file-based locking over NFS. There are two failures, corresponding tothe two ways for things to go wrong when a reply is lost:

• if you lose the server's reply to a successful attempt to acquirethe lock, your replay of the operation will report a failure even thoughyou actually own the lock. The result is effectively a deadlockedsystem where the lock will never get released.

  (This