Client Mail Server Maintenance

     I need to shut the client mail server (provides pop3, imap, smtp for clients and web mail) for just a few minutes to correct a virtual machine setting that is requesting CPU features not supported on the current hardware.  I believe this may be causing some of the instabilities.  At the very least it’s a configuration error that needs to be fixed.

 

Mint – X2Go, NX, RDP, and VNC All Supported Now

     Mint now supports connections to full graphical remote desktops using X2Go, NX, RDP, and VNC connections.  For Androids all the vnc apps I’ve found are broken in that they don’t bring up a keyboard when you click on an input field but aRDP free seems to work and there are probably others.  This gives you a full visual desktop even on android smart phones and tablets.  CentOS 6 also supports all of these protocols.

     Note that RDP will resize to the clients display automatically but vnc opens at 1024×768 resolution.  You can then use either the menus and go to display and alter the resolution or you can use xrandr from a terminal like this:

     xrandr -s 1680×1050

     In this example, setting the display to 1680 wide by 1050 high.

RDP / VNC / NX CentOS6

     In addition to x2go graphical connections, Centos6 now supports RDP (which will automatically size to your screen), NX (which also will automatically size to your screen if you tell it to use the full display), and VNC which starts at 1024×768 but if you go into System->Preferences->Display you can the set it to your native resolution and it will resize the screen accordingly.

Mail Stability

     Today I logged in to the physical machine that the mail virtual host runs on and it died.

     I was able to determine that the cause was an out of memory condition on the machine even though it normally has about 18gb free RAM available.

     I believe it died when I logged in because it was probably a buggy version of x2goserver that caused it.  The x2goserver had been acting weird on that machine, giving me a tiny display instead of a normal full screen display.

     I use a nightly builds version because the stable release is incompatible with the rest of the graphical environment on that machine.  That machine requires xrandr version 1.3 or greater, the stable x2goserver uses version 1.2, but the version in nightly builds uses 1.3.

     The nightly builds may have serious bugs since it is the development version and in this case it appeared it had a bug that ate up all memory.  I have since de-installed and re-installed the x2goserver and all associated libraries and applications.  Now it works properly and it doesn’t crash mail.

     A stable release with this version of xrandr is expected around the second week of February but in the meantime I will not re-install unless there is some other problem.

     I also wrote a small script that runs once a minute and checks to make sure mail is alive and if not boots it so that if this does occur again it will automatically come back up.  It logs it when this occurs with a time stamp so I will be able to examine logs on the machine to see what else was going on at the time it went down.

Mail Is Up ; Future Maintenance

     Mail is backup.  I have a bunch of updates to apply then will need to take down for about twenty minutes to image the machine.

      Also, SSL certificates are currently expired, will fix shortly.  In the meantime just tell your mail client to accept the security exception.

Mail

     The physical host is back up.  This means you can access and receive mail from shell servers.

     I am working on restoring the virtual machine mail from an earlier backup before instabilities crept in.

Mail Server

     The mail server crashed again this afternoon.  In an attempt to fix it rather than just reboot again I decided to restore from a backup made prior to the time it started acting up.

     During the restoration the physical host hung so I will need to drive down to the co-location facility to restore the physical server then finish bringing mail backup.