August 2009 System Upgrades

There's only a two-week "window" in which I can perform these upgrades with the least impact on the Nevis research groups.

General procedure

  • System upgrades will start at 3PM of the given day.
  • Unless otherwise noted, the upgrades will take 2-3 hours.
  • If you see "this will affect e-mail/logins...", then:
    • The accounts listed won't be able to login or use e-mail during the upgrade;
    • For everyone else, I'll reboot the mail and web servers sometime between 3:00-3:15PM; I hope this will reduce the chance of a mail-server slowdown. It's a good idea for you to quit your e-mail program during that time.


This is the list of systems I plan to upgrade on a given day.

Monday, August 10


This will affect e-mail/logins for grace.ho, willis, an2262, zhang.

Tuesday, August 11


This will affect the e-mail/logins for most of the Neutrino group.

Wednesday, August 12


If all goes well, no one's e-mail be affected, nor will any other visible aspects of the Nevis cluster.

Thursday, August 13


This will also affect the e-mail/logins for any members of ATLAS with home directories on kolya.

Monday, August 17


During these upgrades, condor will not be available. No Nevis mailing lists will be available. This will also affect the e-mail/logins for members of the DOE group, as well as shaevitz, annmarie, jsantini, bishop, capone, and sciulli.

Tuesday, August 18


This may cause a Nevis-wide slowdown of all systems, since karthur is the library server. This will also affect the e-mail/logins for members of D0 and those members of ATLAS with home directories on karthur, including ban.

Wednesday, August 19


This is our mail server. The upgrade will take 4-5 hours. During the upgrade, Nevis e-mail will not be available.

Incoming e-mail won't be lost. It will be stored on the backup mail server in the Nevis Annex until the mail server comes back on.

Thursday, August 21


This is our web server. The upgrade will take 4-5 hours. During the upgrade, all Nevis web services (including the Wiki, meeting-room schedules, calendars, etc.) will not be available.

What is the nature of the upgrade?

Unless otherwise noted, the Nevis cluster systems are being "upgraded" from Fedora 9 to Scientific Linux 5.3. That word is in quotes because the Scientific Linux 5 packages are earlier versions than those in Fedora 9, and the distribution has fewer features.

There is no "upgrade path" from Fedora 9 to Scientific Linux 5.3; I have to completely re-install the operating system. For some systems with a complex configuration, it would take too long to re-create those configurations in SL5.3. Therefore, the following systems being upgraded from Fedora 9 to Fedora 11, which will preserve the configuration information:

  •, the central admin server
  •, the mail server
  •, the web server
  •, the Annex server

Upgrade problems

I've immediately encountered a severe problem with upgrading the Nevis servers: Scientific Linux cannot read the disk-partitioning scheme I've used.

This means that, in order to preserve the /data partition on your system, I have to copy it to another machine, then restore it again. This saturates the Nevis network, and can take a substantial portion of a day.

Please delete anything that you don't need, or can quickly restore, from the /data partition of your server. If you can, please tell me that I don't have to restore your /data partition, or tell me I can delete file left behind by summer student, etc.

Remember, the more you leave on /data, the longer your system's upgrade will take.

The specific issue: Fedora Linux can handle logical volumes (LVM) on top of software RAID. Scientific Linux cannot. This is causing problems with hogwarts and polaris; a two-hour upgrade turned into an eight-hour nightmare. It remains to be seen whether Scientific Linux has a problem with systems that use hardware RAID or LVM created under Fedora: riverside, morningside, karthur, kolya, shang, han.

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Topic revision: r8 - 2009-08-10 - WilliamSeligman
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