Date: Tuesday, June 9, 2026 (06:00-18:00)

Who is affected:
ALL users of CS Department (or University) cluster computing systems
AND
ALL users of research rack space at the HPCRC (151 Forrestal Road)

What is happening:
On June 9, 2026, all “A”-side power at the HPCRC will be turned off and
unavailable for the full business day while preventative major maintenance
is performed on the building’s power systems. “A”-side power accounts for
half the power to the building, and ALL of the power to most racks occupied
by the Computer Science Department.

ALL researchers with equipment in HPCRC racks should anticipate that they
will lose power at 07:00 and not regain power before 15:00. It is
recommended that researchers arrange to power off their equipment prior to
the 07:00 start time and be prepared to check its health and restore
services after the 15:00 end. CS Staff is announcing a wider 12-hour window
to allow for this time to orderly shut down clusters, and to power back on
after the work.

ALL ionic and neuronic cluster resources will be offline and unavailable.
ALL courselab and armlab systems will be offline and unavailable.
The “cycles” systems will be rebooted at the start of the window, but are
anticipated to be available.
All other central CS services (e.g. email, web service, storage) are
anticipated to remain available.

OIT’s announcement of this maintenance can be found here:
oit.princeton.edu/events/hpcrc-planned-downtime-maintenance

Why is it happening:
The power equipment at the HPCRC is overdue for major maintenance to reduce
the risk of unplanned failures and outages. This maintenance window, and a
related upcoming outage on October 20, will allow for this maintenance to
be performed safely.

The October 20 outage will be announced separately later in the Summer and
will be essentially identical to this one, but affecting the “B”-side
power.

We will post updates to the status page: 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.

Sincerely,
CS Staff

Hello, everyone.

This is a reminder that we are one week away from the CS Cycles/Ionic/Neuronic Systems downtime.

Thank you,
CS Staff

—– Forwarded Message —–
From: csstaff@cs.princeton.edu
To: downtime@lists.cs.princeton.edu
Sent: Tuesday, December 16, 2025 9:05:04 AM
Subject: [downtime] CS Cycles/Ionic/Neuronic Systems Downtime, Tuesday, January 13, 2026, 07:00-15:00

Date: Tuesday, January 13, 2026 (07:00-15:00)

Who is affected:
All users of the CS Department Beowulf high performance computing clusters,
known as ionic and neuronic.

All users of the CS Staff-managed public login systems, including the
cycles, courselab, and armlab systems.

What is happening:
CS Staff will upgrade the Ionic and Neuronic clusters, as well as the
Cycles, Courselab, and Armlab systems, to the latest Red Hat 9
distribution.

In addition, the cluster management and job scheduling system, Slurm, along
with its database, will also be upgraded. No data loss is anticipated.

Why is it happening:
This is part of the routine maintenance and will bring newer versions of
installed tools and software.

We will post updates to the status page: 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.

Sincerely,
CS Staff

Date: Tuesday, January 13, 2026 (07:00-15:00)

Who is affected:
All users of the CS Department Beowulf high performance computing clusters,
known as ionic and neuronic.

All users of the CS Staff-managed public login systems, including the
cycles, courselab, and armlab systems.

What is happening:
CS Staff will upgrade the Ionic and Neuronic clusters, as well as the
Cycles, Courselab, and Armlab systems, to the latest Red Hat 9
distribution.

In addition, the cluster management and job scheduling system, Slurm, along
with its database, will also be upgraded. No data loss is anticipated.

Why is it happening:
This is part of the routine maintenance and will bring newer versions of
installed tools and software.

We will post updates to the status page: 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.

Sincerely,
CS Staff

Hello, everyone.

In order to accommodate several research and conference deadlines that were brought to our attention, we have adjusted the maintenance window to Wednesday, November 19 at 5:00 am.

Thank you,
CS Staff

—– Original Message —–
From: csstaff@cs.princeton.edu
To: downtime@lists.cs.princeton.edu
Sent: Monday, November 3, 2025 9:24:13 AM
Subject: [downtime] CS Storage Maintenance, Wednesday, November 12, 2025, 09:00-15:00

Date: Wednesday, November 12, 2025 (09:00-15:00)

Who is affected:
All users of the CS department storage or computing facilities.

What is happening:
We are upgrading our storage operating system, which requires the
components of the CS storage system to be rebooted. This upgrade is
expected to be mostly non-disruptive, and department services will continue
as usual, but sporadic moments of interruption may be noticeable at times.

All services that depend upon access to storage share the same minor risk
of performance hiccups for some periods during this window, including cycle
servers, ionic and neuronic clusters, web content, home directories, CIFS,
etc.

Why is it happening:
In July, we identified that a filesystem bug affecting critical shared
storage was causing intermittent failures of some of our web services. This
problem, which occasionally restricted required access and disrupted site
availability, and had no viable workaround, has been under review while we
awaited an official fix from Dell. During the upcoming upgrade, we will
apply the newly released OneFS patch to resolve this issue and enhance
overall service reliability.

We will post updates to the status page: 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.

Sincerely,
CS Staff

Date: Wednesday, November 12, 2025 (09:00-15:00)

Who is affected:
All users of the CS department storage or computing facilities.

What is happening:
We are upgrading our storage operating system, which requires the
components of the CS storage system to be rebooted. This upgrade is
expected to be mostly non-disruptive, and department services will continue
as usual, but sporadic moments of interruption may be noticeable at times.

All services that depend upon access to storage share the same minor risk
of performance hiccups for some periods during this window, including cycle
servers, ionic and neuronic clusters, web content, home directories, CIFS,
etc.

Why is it happening:
In July, we identified that a filesystem bug affecting critical shared
storage was causing intermittent failures of some of our web services. This
problem, which occasionally restricted required access and disrupted site
availability, and had no viable workaround, has been under review while we
awaited an official fix from Dell. During the upcoming upgrade, we will
apply the newly released OneFS patch to resolve this issue and enhance
overall service reliability.

We will post updates to the status page: 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.

Sincerely,
CS Staff

Date: Tuesday, August 5, 2025 (06:00-11:00)

Who is affected:
All users of the CS department storage or computing facilities.

What is happening:
We are upgrading our storage operating system, which requires the
components of the CS storage system to be rebooted. This upgrade is
expected to be mostly non-disruptive, and department services will continue
as usual, but sporadic moments of interruption may be noticeable at times.

All services that depend upon access to storage share the same minor risk
of performance hiccups for some periods during this window, including cycle
servers, ionic and neuronic clusters, web content, home directories, CIFS,
etc.

Why is it happening:
An upgrade is required to address a bug that is causing unreliable snapshot
expiration, generating unnecessary costs.

While we do not anticipate any extended service outages, you may find that
there are momentary interruptions, and some connections (especially
CIFS/SMB connections) may need to be reestablished.

We will post updates to the status page: 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.

Sincerely,
CS Staff

Date: Tuesday, July 15, 2025 (07:00-15:00)

Who is affected:
All users of the CS Department Beowulf high performance computing clusters,
known as ionic and neuronic.

All users of the CS Staff-managed public login systems, including the
cycles, courselab, and armlab systems.

What is happening:
CS Staff will upgrade the Ionic and Neuronic clusters, as well as the
Cycles, Courselab, and Armlab systems, to the latest Red Hat 9
distribution.

In addition, the cluster management and job scheduling system, Slurm, along
with its database, will also be upgraded. No data loss is anticipated.

Why is it happening:
This is part of the routine maintenance and will bring newer versions of
installed tools and software.

We will post updates to the status page: 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.

Sincerely,
CS Staff

Date: Tuesday, July 1, 2025 (06:00-16:00)

Who is affected:
All users of the CS department storage or computing facilities.

What is happening:
We are upgrading our storage operating system, which requires the
components of the CS storage system to be rebooted. This upgrade is
expected to be mostly non-disruptive, and department services will continue
as usual, but sporadic moments of interruption may be noticeable at times.

All services that depend upon access to storage share the same minor risk
of performance hiccups for some periods during this window, including cycle
servers, ionic and neuronic clusters, web content, home directories, CIFS,
etc.

Why is it happening:
Our current operating system has reached end-of-life status and needs an
upgrade.

While we do not anticipate any extended service outages, you may find that
there are momentary interruptions, and some connections (especially
CIFS/SMB connections) may need to be reestablished.

We will post updates to the status page: 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.

Sincerely,
CS Staff

Date: Monday, June 9, 2025 (07:30-08:00)

Who is affected:
All users of CS Department networked services, including email, web
service, and HPC computing.

What is happening:
Critical backbone switches will be upgraded to newer firmware and
rebooted.

We expect no lasting negative impacts from this maintenance.

Why is it happening:
Firmware upgrades are necessary on a few devices to address bugs that are
slowing progress on our Summer project list.

We will post updates to the status page: 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.

Sincerely,
CS Staff