HMC Mathematics Computing Weblog

At this point I'm done rebooting systems. As far as I can tell so far, everything went well. We're now running the current kernels on everything, and things seem to be working the way I would expect them to work. I will be keeping an eye on the systems to make sure that nothing unusual starts happening; should you notice any problems, I would very much appreciate knowing about them.

I have moved the current CentOS and CTAN mirrors off yum.math.hmc.edu and on to our new mirror server, http://mirror.hmc.edu/.

The new base URLs for these mirrors are

CentOS

http://mirror.hmc.edu/centos/

CTAN

http://mirror.hmc.edu/ctan/

For the time being, I have set up redirects so that attempts to retrieve data from URLs pointing to yum will automatically be redirected to mirror.hmc.edu.

At some point the machine that the old mirror server runs on may be retired or repurposed, so if you're using our CentOS mirror to update your machines or our CTAN mirror to download TeX-related material, I would encourage you to change the URLs in your YUM configuration files to point to the new location.

When

I will be doing some systems work this weekend, June 7--8.

Work will probably begin around 11:00 AM on Saturday, June 7, and will continue for several hours. If necessary, additional work may be done on Sunday, June 8, within a similar block of time.

What Will Be Affected

The work will disrupt most of our networked services, including e-mail, file service, interactive sessions, and the web server for periods of several minutes to an hour over the course of the work.

I also want to make sure that all of our Macs are running the latest security updates, so will be updating these machines during this time period as well.

What You Should Do

If you're using a Mac or Linux system that mounts file systems from our servers, before you leave on Friday evening,

• Save all open files;
• Close all applications;
• Log out;
• Leave your machine running.

Why

This work is necessary for us to ensure the security and improve the stability of the overall system. In particular, I am hoping that ongoing issues with our web server will be resolved as a result of this work.

I will do my best to keep as much of the system functional as possible for as much of the time as I can, but there will still be some outages.

Additional Background

Last semester we had some serious issues with interactions between the NFS support on our new file server and on our workstations and older servers, exacerbated by the HVAC failure. I was able to stabilize things, but we still see some flaky behavior (especially From the web server, which needs to be rebooted periodically).

On the Linux server side, I plan to update to the latest kernel releases and do some experimentation to see if everything will work together happily. I will need to reboot various servers and workstations an arbitrary number of times to explore all the possible interactions.

For Macs, I will install the latest updates, most of which require the machines to be rebooted. As Tiger (Mac OS X 10.4) has problems when an NFS server disappears and reappears, these machines would need to be rebooted anyway.

Comments/Problems/Other Issues

As usual, if there are problems with the scheduling of this work, requests or any other comments, please let me know.

Updates/Status Reports

As usual, updates on the status of the systems and progress reports will be posted to the ``sysblog'', on our web server at

http://www.math.hmc.edu/computing/blog/>

Thanks for your cooperation!