[Nebula-users] Fahrenheit available

[Peter Bortas]

Dear Nebula users,

Fahrenheit is now online with 16 of 48 nodes available. We urge you to
move your research workloads from Nebula to Fahrenheit as soon as
possible. More nodes will be made available on demand as we can turn
off Nebula nodes. The deadline for porting jobs is the end of March
(before Easter), but the sooner the better.

We currently have a few accounts in the creation pipeline that will
get done today. If you think you should have an account on Fahrenheit
but have not received an invite by Wednesday then contact Martin.

All Nebula projects are also available on Fahrenheit. Please recompile
all code and review all job/submit scripts when porting. Do NOT
reserve full nodes on Fahrenheit (no --exclusive flags) unless you
have discussed it with Martin first.

Note that there are only "thin" nodes in Fahrenheit, but they have
almost as much memory as a "fat" node has in Nebula.

When allocating anything larger than the minimal allocation use the -n
flag to specify number of cores. -n 50 will give your job 50 cores, -n
50 --ntasks-per-core=2 will give your job 25 cores with the appropriate
Slurm environment variables set to indicate that hyper-threading should
be used if your application is sensitive to that.

Avoid using flags that specify how much memory the job should
get. Just allocate more cores to get more memory.

Fahrenheit has the exact same hardware configuration of nodes as
Kelvin and Celsius if you have had access to those earlier:

CPU: 2 x AMD EPYC 9565 72-Core Processor (288 threads per node)

RAM: 768 GiB (About 2.5GiB per thread)

Local storage:
NVME flash in $SNIC_TMP. Size depends on how large part of the node
you have allocated.

Common storage:
The exact same storage as on Nebula. The new cluster is hooked up to
the same storage servers. That also means any change done in you /home
or in /nobackup on Nebula OR Fahrenheit will immediately show up on
the other cluster. So take some care that you copy any project script
to a new directory before modifying it on Fahrenheit if you want to
keep the old scripts running unmodified on Nebula for now.

Questions about porting/migration from Nebula to Fahrenheit may be
directed to martinls at met.no

Regards,
--
Martin Lilleeng Sætra and Peter Bortas