Category archives: Tech Zone

ssh, sudo and X forwarding

After you ssh into a unix/linux box and sudo into another user account, you get:

X11 connection rejected because of wrong authentication.

Solution

$ echo $DISPLAY

You get something like:

localhost: 11.0

Then do:

$ xauth list

and you’ll see something like:

$ xauth list $DISPLAY You’ll get something like:

somehost/unix:1o MIT-MAGIC-COOKIE-1 ee4873663c9ddfaeae3283b64230891b

Then, after having done sudo, tell the new user what the cookie is:

$ xauth add somehost/unix:12 MIT-MAGIC-COOKIE-1 ee4873663c9ddfaeae3283b64230891b

Done!

VMWare Fusion 4

Today I upgraded my VMWare Fusion from verison 3 to version 4.  The most critical change I’ve found so far is in the location for networking/dhcp/nat configuration files.  Fusion 4 now locates those config files in: /Library/Preferences/VMware Fusion/vmnet8.

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=1026510

I will add more info to this post as soon as I have more to share.  I’m hoping Fusion 4 is more efficient in utilizing the host resources and better performing.  I already like the interface design that is more integrated and seamless for Lion.

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Google Chrome could not open your profile on NFS partition

One day, I started seeing an odd pop up every time I started google chrome on my linux box at work.  If I just click the ‘OK’ button, chrome would work just fine.  The pop up is quite annoying though.

After some research, I found that this is caused by NFS server locking your profile.  My home directory on my linux box is located on an NFS mounted partition (part of an NIS infrastructure).  Its quite known that for some reasons an NFS server can lock SQLLite files and never reqlinquish the lock.  That’s precisely what happened to my chrome profile.

To remove the lock, you would need to, kind of, relocate the file nodes.  You can do the following to achieve that:

  • cd ~/.config/google-chrome
  • mv Default Default.bak
  • cp -r Default.bak Default
  • restart your google chrome browser
  • then you can remove the old Default.bak directory

MySQL/InnoDB – ‘Unable to lock’ issue

Today, one of our MySQL database suddenly went unresponsive. The first thing I noticed was the following lines in the error.log:

InnoDB: Unable to lock /path/to/ibdata1, error: 11
InnoDB: Check that you do not already have another mysqld process
InnoDB: using the same InnoDB data or log files.

Upon further investigation, I found a not perfectly matched issue but does look similar: http://forums.mysql.com/read.php?22,22344,24497#msg-24497.  I took a chance and did the following:

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