Author: ssarajlic3

All nodes and GPFS filesystem issues affected from the power failure should be resolved as of late Friday evening (June 16) . If you are still experiencing problems, please let us know at pace-support@oit.gatech.edu.

We are experiencing intermittent problems with the GPFS storage system that hosts most of the project directories.

We are working with the vendor to investigate the ongoing issues. At this moment we don’t know whether they are related to yesterday’s power/cooling failures or not, but we will update the PACE community as we find out more.

This issue has potential impact on running jobs and we are sorry for this inconvenience.

Impacted Queues:

Update (6/7/2017, 1:20pm): The network issues are now addressed and systems are back in normal operation.Please check your jobs and resubmit failed jobs as needed. If you continue to experience any problems, or need our assistance for anything else, please contact us at pace-support@oit.gatech.edu. We are sorry for this inconvenience and thank you once again for your patience.

Original message: We are experiencing a large scale network problem impacting multiple storage servers and software repository with a potential impact on running jobs. We are currently actively working to get it resolved and will provide updates as much as possible. We appreciate your patience and understanding, and are committed to resolving the issue as soon as we possibly can.

PACE clusters and systems will be taken offline at 6am this Thursday (May 11) through the the end of Saturday (May 13). Jobs with long walltimes will be held by the scheduler to prevent them from getting killed when we power off the nodes. These jobs will be released as soon as the maintenance activities are complete.

Planned improvements are mostly transparent to users, requiring no user action before or after the maintenance.

Systems

• We will deploy a recompiled kernel that’s identical to the current version except for a patch that addresses the dirty cow vulnerability. Currently, we have mitigation in place that prevents the use of debuggers and profilers (e.g. gdb, strace, Allinea DDT, etc). After the deployment of the patched kernel, these functions will once again be available for all nodes. Please let us know if you continue to have problems debugging or profiling your codes after the maintenance day.

Storage

• Firmware updates on all of the DDN GPFS storage (scratch and most of the project storage)

Network

• Upgrades to DNS servers, as recommended and performed by OIT Network Engineering
• Software upgrades to the PACE firewall appliance to address a known bug
• New subnets and re-assignment of IP addresses for some of the clusters

Power

• PDU fixes that are impacting 3 nodes in c29 rack

The date for the next maintenance day is not certain yet, but we will announce it as soon as we have it.

Starting 5:10 pm 11 April 2017, COE license servers are available again.

Multiple Georgia power outages are plaguing multiple license servers on campus. All efforts have been made to keep systems available. If your jobs report missing or unavailable licenses, please check http://licensewatcher.ecs.gatech.edu/ for the most up to date information.

College of Engineering (COE) license servers will go dark at 3:35pm. Research and Instruction to be impacted.

COE system engineers have stated: Running out of UPS run time. Ansys / Comsol / Abaqus / Solidworks and other software will go dark. Matlab / Autocad and NX should still be up (running in a different location).

As some of you are already aware, the dirty cow exploit was a source of great concern for PACE. This exploit can allow a local user to gain elevated privileges. For more details, please see “https://access.redhat.com/blogs/766093/posts/2757141”.

In response, PACE has applied a mitigation on all of the nodes. While this mitigation is effective in protecting the systems, it has a downside of causing debugging tools (e.g. strace, gdb and DDT) to stop working. Unfortunately, none of the new (and patched) kernel versions made available by Red Hat supports our Infiniband network drivers (OFED), so we had to leave the mitigation running for a while. This caused inconvenience, particularly for users who are actively developing codes and relying on these debuggers.

As a long term solution, we patched the source code of the kernel and recompiled it, without changing anything else. Our initial tests were successful, so we deployed it on three of the four online nodes in the testflight queue:

rich133-k43-34-l recompiled kernel
rich133-k43-34-r recompiled kernel
rich133-k43-35-l original kernel
rich133-k43-35-r recompiled kernel

We would like to ask you to please test your codes on this queue. Our plan is to deploy this recompiled kernel to all of the PACE nodes, including headnodes and compute nodes. We would like to make sure that your codes will continue to run after this deployment without any difference.

The deployment will be a rolling update, that is, we will opportunistically patch nodes starting from the idle nodes. So, there will be a mix of nodes with old and recompiled kernels in the same queues until the deployment is complete. For this reason, we strongly recommend testing multi-node parallel applications that will include the node with the original kernel (rich133-k43-35-l) in the hostlist to test the behavior of your code with mixed hostlists.

As always, please keep your testflight runs short to allow other users to test their own codes. Please report any problems to pace-support@oit.gatech.edu and we will be happy to help. Hopefully, this deployment will be completely transparent to most users, if not all.

PACE and other systems in the Rich 133 computer room experienced a brief power event on the afternoon of Monday, January 30th. This power event involved significant failure of one of the three uninterruptible power supply (UPS) systems that supply the Rich computer room with stable, filtered power. The UPS system switched over to bypass mode as designed and one of the main power feeder transfer switches also experienced a failure. Stable power continued to the PACE systems and all systems and network devices continued to operate without interruption.

Repair of the failed UPS is underway but parts may not be available for up to two weeks. During this time, the UPS power system will remain in bypass mode connecting many of the PACE systems to standard campus power. Our experience shows the campus power is usually clean enough to operate normally and so we are operating normally. Repair and re-testing of the UPS can take place without interruption of the existing power. We will announce this repair transition when we have additional information.

Should there be any significant campus power interruption during this interim time, we may lose power to some of the PACE systems. Rest assured the PACE staff will do our best to recover all systems affected by such an event. We will keep you informed via blog and announcement mailing lists of the repair progress.