[downtime] CS HPC Cluster Downtime, Tuesday, March 15, 2016,

Date: Tuesday, March 15, 2016 (08:00-14:00)

Who is affected:
All users of the CS Department HPC Cluster (ionic.cs.princeton.edu).

What is happening:
On this day, the “ionic” cluster will be reinstalled and upgraded to the
latest OS distribution version, Springdale 7.2. This is a complex upgrade,
which is the reason for the unusually long outage window.

SPECIAL NOTE: As we are reloading the operating system, any crontabs on the
cluster will be lost. If you have crontabs that you wish to persist, you
will need to back up your crontabs before the downtime, and restore them

Why is it happening:
This is part of normal maintenance of the publicly-accessible systems, and,
along with the patching of the cycles and penguins machines (announced
separately), will bring our primary public computational systems into
harmony running the same versions of Springdale Linux.

Please note that with this upgrade, some older versions of software, or
some packages which are no longer part of the distribution, may no longer
be available. We encourage you to verify your workflows after this upgrade
to ensure you are able to continue your work. CS Staff stands ready to
assist with any unforeseen trouble.

For most workflows, it should be possible to test your code on the cycles
machines in advance of the upgrade, as they are already running a version
of Springdale Linux that is close to the version to be installed during
this window. Some things will likely still differ after the upgrade, since
the cycles machines will also be updated, but the cycles machines are
receiving only minor updates, so breaking changes should be few or none.

We will post updates to the status page: http://www.csstaff.org
as necessary.

If this downtime will cause you undue hardship, please contact
csstaff@cs.princeton.edu immediately, so we can discuss options to reduce
any negative impact. Your patience is appreciated.

CS Staff
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