PACE A Partnership for an Advanced Computing Environment

January 12, 2017

PACE quarterly maintenance – January 2017

Filed under: tech support — admin @ 9:36 pm

Dear PACE users,

It is again time for our quarterly maintenance. Starting at 6:00am Thursday, January 19, all resources managed by PACE will be taken offline. Maintenance is scheduled to continue through Saturday evening. Our next maintenance period is scheduled for Thursday May 11 through Saturday May 13, 2017.  We have a reduced scope this time around, as compared to our previous maintenance periods, with only one item visible to users.

Removal of obsolete /usr/local/packages
We will be removing (nearly) all content from /usr/local/packages. This set of software represents a repository two versions old, much of which is incompatible with the currently deployed operating system. We believe that this software is not currently in use – with one exception. We will continue to work with that user to accommodate their needs. Newer and/or compatible versions of all software being removed are available in the current repository.

Old modules, including the module that has been used to access to this old repository (oldrepo) will be removed. If attempt to load this module(s) in your environment or in PBS scripts, you will get an error. Please contact if you need assistance with finding replacement modules in the current repository.

Infiniband switch swap
We will replace a small infiniband switch used by infrastructure servers with one that has redundant power supplies. This was identified during the recent electrical maintenance by OIT. No user action is required.

Readdressing network management
With the assistance of the OIT Network Engineering team, we will move the management IP addresses for a number of network devices. This will make room for additional user-facing services. As these devices are not accessible to the user community, no user action is required.

Upgrade of scheduler server for the NovaZohar cluster
The scheduler server responsible for the NovaZohar cluster will be upgraded during the maintenance period. This will provide for additional performance for scheduler related tasks (submitting jobs, querying status, etc.) Previously submitted jobs will be retained, and resumed at the conclusion of maintenance. No user action is expected.

December 23, 2016

holiday support and PACE staffing

Filed under: tech support — admin @ 6:43 pm

Greeting, and Happy Holidays!

Please note that all PACE clusters will continue to operate during the GT Institute Holiday. However, PACE staff will not be generally available for support. The Rich building will be closed and the OIT Operations staff will also be unavailable over the holiday, though available via phone. If you become aware of a catastrophic, system-wide failure please notify OIT Operations at (404) 894-4669. They will be able to get in touch with us.

On a much more somber note, Ms. Josephine Palencia, one of the PACE Research Scientists, will be leaving the team for a position in industry, effective January 4. This leaves PACE in a very difficult position with 4 vacant full time positions from a team of 11.5 FTEs. We will continue to do our best to keep things operational, however delays are unavoidable while we complete the respective hiring searches. Please direct interested parties to

December 16, 2016

Power maintenance 12/19/2016 (Monday)

Filed under: tech support — Semir Sarajlic @ 9:21 pm

(No user action needed)

We have been informed GT Facilities will perform critical power maintenance beginning at 6am Monday 12/19/2016, in one of the PACE datacenters.

We believe, after a careful investigation, PACE systems should have sufficient power redundancy to allow the careful work to be completed without required downtime or failure. However, there is always a small risk that some jobs or service will be impacted. We will work closely with the OIT operations and facilities teams to help protect running jobs from failures. We will keep all PACE users informed of progress or should failures occur.

November 2, 2016

PACE scratch storage is now larger and faster

Filed under: tech support — Semir Sarajlic @ 3:36 pm

We have increased the capacity of the scratch storage from ~350TB to ~522TB this week, matching the capacity of the old server (Panasas) that was decommissioned back in April. The additional drives were installed without any downtime, with no impact on jobs.

This also means larger number of drives contributing to parallel reads and writes, potentially increasing the overall performance of the filesystem.

No user action needed, and you should not see any differences in the way you are using the scratch space.

October 15, 2016

PACE clusters ready for research

Filed under: tech support — admin @ 10:26 pm

Our October 2016 maintenance period is now complete. We’ve compute nodes, login nodes and interactive (post-processing) nodes to the RedHat Enterprise Linux 6.7 previously deployed on the TestFlight cluster.  This included a large number of bugfix and security patches, a major step forward in the Infiniband layer and recompiled versions of various MPI, scientific libraries and applications in /usr/local.  Please do let us know (via email to if you see issues with your jobs.

We have brought compute nodes online released previously submitted jobs. As usual, we have a number of compute nodes that still need to be brought back online, but we are actively working to make them available asap.

Hardware repairs to the project directory (~/data) system is complete.  Minor repairs to the scratch system will be rescheduled for a future maintenance period.  The issue is minor and should not disrupt performance or availability of the scratch system.  No user actions are expected.

The OIT Network Engineering team upgraded the software running on many of our switches to match that which is running elsewhere on campus.  This included our firewalls.  No user actions are expected.

Electrical work
These problems were a bit more extensive than originally anticipated.  With some help from the OIT Operations team, we have a alternate solution in place, and will complete this work at a future maintenance period.  No user action is expected.

Bonus objectives
We were able to add capacity to the project directory system, and we now have our first single filesystem that’s greater than a petabyte, coming at about 1.3PB.  Maybe that’ll last us a couple of weeks.  😉  Disks for the scratch system have been installed, we will add them into the scratch filesystem shortly.  This can be done live without impact to running jobs.

October 10, 2016

PACE quarterly maintenance – October 2016

Filed under: tech support — admin @ 11:01 pm

Dear PACE users,

It is again time for our quarterly maintenance. Starting at 6:00am Thursday, October 13, all resources managed by PACE will be taken offline. Maintenance is scheduled to continue through Saturday evening. Our next maintenance period is scheduled for January 19-21, 2017.

As previously posted, our major activity this time around will be an upgrade of all compute nodes, head nodes and interactive nodes from RedHat 6.5 to RedHat 6.7. This is simply deploying the operating system and software repository we been testing internally and have made available on the TestFlight cluster for the broader PACE community to perform testing as well. I’ll issue one more plea for additional testing to the user community and ask that you report experiences, either positive or negative, to

We have some hardware repairs to perform on both DDN devices. Internal redundancy has prevented any availability or integrity problems so we’ll take advantage of the downtime for DDN engineers to make repairs. No user action is expected.

The OIT Network Engineering team will be upgrading the software running on a number of PACE network devices. These updates are for stability and have been running on similar devices in the campus network for some time. No user action is expected.

Electrical work
OIT Operations will be replacing some faulty rack-level power distribution in a couple of racks. No user action is expected.

Bonus objectives
If sufficient time remains in the maintenance period, we will add capacity to both the GPFS scratch and project systems. We are able to perform these activities during normal operations, so we will prioritize bringing things back into operation as soon as possible.

September 30, 2016

Headnode GPFS Problem

Filed under: tech support — Semir Sarajlic @ 3:53 am

About 8:30pm this evening, one of the PACE systems that provides services to the GPFS files to headnodes and other PACE internal systems failed. When this happens, users may see the message “stale file handle” or you may notice there are no files under the /gpfs directory. This is a temporary condition that should be fixed shortly.

Please note: All files that were already written and all files accessed or written by any compute node are unaffected. However, if you were in the process of editing a file on a headnode, only your most recent changes may be unavoidably lost. In addition, any process you may have had running on a headnode system using these files may have been killed due to this failure.

To prevent this from recurring, PACE had ordered and very recently received a new computer to replace the system that failed this evening. Our staff will undertake the testing and replacement as soon as possible and we will post an announcement here once the new system is in service.

We apologize for this inconvenience and thank those users who let us know quickly.

September 22, 2016

TestFlight cluster available with RHEL6.7

Filed under: tech support — admin @ 5:57 pm

The TestFlight cluster is now available with the updated RHEL6.7 load, as well as some recompilations of software in /usr/local. Please, do login to and try submitting your jobs to the ‘testflight’ queue. If you have any problems, please send a note to

September 13, 2016

PACE quarterly maintenance – October 2016

Filed under: tech support — admin @ 9:38 pm

Dear PACE users,

Quarterly maintenance is fast approaching. Starting at 6:00am on Thursday, October 13, all resources managed by PACE will be taken offline. Maintenance will continue through Saturday evening unless we are able to finish sooner.

Our major activity this maintenance period will be an operating system upgrade for all compute nodes, head nodes and interactive nodes. This update will take us from RedHat 6.5 to RedHat 6.7, and includes important security and bug fix updates to the operating system, a new Infiniband layer and some recompiled versions of existing /usr/local software. Some applications have shown increased performance as well.


PACE staff have been testing this upgrade using various existing applications but we need your help to ensure a smooth rollout. As of today, we have begun applying these updates to our TestFlight cluster, which is available for all to use. We’ll send out a follow up communication when it is ready. PLEASE, PLEASE, PLEASE, use the next few weeks to try your codes on the TestFlight cluster and send feedback to We would especially like to hear of any issues you may have, but reports of working applications would be helpful as well.

Our goal is to provide the best possible conversion to the updated operating system, and ask that you please take the opportunity to help us ensure a smooth transition back into normal operation by availing yourself of the TestFlight cluster.

August 25, 2016

localized network outage has some nodes offline

Filed under: tech support — admin @ 4:21 pm

At approximately 10:40 this morning, the failure of a top-of-rack network switch in the P31 rack of our data center failed. This caused a loss of network connectivity for approximately 44 compute nodes across a wide variety of queues. (see below) No other compute nodes are affected. Jobs running on these nodes will likely have failed as a result. The OIT network team is swapping in a replacement at the moment, and PACE staff are working to restore service as quickly as possible.

If you have access to any of the queues below, please check on their status and resubmit as needed. You can check which queues you have access to by using the ‘pace-whoami’ command.

We apologize for the inconvenience, and will work to bring these nodes back online as soon as possible.  If you have additional questions, please email


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