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29.11.2021 Change to Memory Management settings

On 29.11.2021 we will change two operating system settings affecting memory management on HoreKa. We expect that these changes can make your applications run faster.

Enablement of "Transparent Huge Pages"

The size of memory pages will be increased. This decreases the memory management overhead for many memory access patterns, resulting in a speedup.

More information can be found here. The value will be set to "always".

Activation of "zone_reclaim_mode"

More intensive attempts than before are made to create new memory pages in the NUMA-domain (CPU socket) in which the associated process is running. This avoids (slower) memory accesses to the memory of other CPU sockets.

More information can be found here. The value will be set to "1" (Zone reclaim on).

Maintenance 12.07. - 16.07.2021

From July 12th 9:00 am until July 16th noon no compute nodes will be available on HoreKa and HAICORE, so no jobs will run. Additionally, individual login nodes will be unavailable for some time during this interval, which will also affect the Jupyter and CI services.

Maintenance 28.05.2021

HoreKa will go into full operation on 01.06.2021 as planned. To perform the last preparatory steps, a planned maintenance interval has taken place on

Friday, 28.05.2021 between 08:00 and 15:00

The login nodes have been reinstalled and restarted. Running jobs have not been aborted. Waiting jobs have started automatically after maintenance was completed. Data on the parallel file systems was preserved, data stored locally on the nodes (e.g. in /tmp) has been deleted.

Please note that the following major changes have taken place:

  • The configuration of the batch system partitions has been adjusted. In particular, the memory limit for some node types in the queue "cpuonly" has been reduced to 1600 MB per CPU. Please check the updated information and adjust your job scripts if necessary.

  • The Python modules devel/python/2.7 and devel/python/3.6 have been renamed to devel/python/2.7_intel and devel/python/3.6_intel. Please note that you do not need to load a module to use the default system Python version 3.6.8.

  • Python version 3.8 has been made available in addition to the default system version 3.6.8. You can either use the python3.8 and pip3.8 commands to explicitely request this version. Or you can load the devel/python/3.8 module, which will override the python and pip commands.

Last update: November 22, 2021