Working on Maxwell

===== Maxwell Resources =====

The [[Maxwell Hardware >>url:https://confluence.desy.de/display/IS/Maxwell+Hardware||shape="rect"]]is partitioned in different partions which will be upgraded constantly. The concept is that all integrated hardware is available via the {{code language="none"}}ALL{{/code}} partition ({{code language="none"}}ALLGPU{{/code}} for nodes with integrated GPU), but the job will be terminated when a job with a higher priority (from the nodes owner) comes in. Dedicated to Photon Science are the {{code language="none"}}PS{{/code}} (internal users) and {{code language="none"}}PSX{{/code}} (external users) partitions. Regarding GPUs (Mai 2019) the PS partition has nodes with a single NVIDEA Tesla P100 while the PSX partition has no GPUs at all.

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For interactive code development (including 4 NVIDIA Quadro M6000 ) and running short jobs (as shared resource) the Maxwell Display Server is foreseen. Dedicated nodes will be available via [[Slurm Jobs>>url:https://confluence.desy.de/display/IS/Running+Jobs+on+Maxwell||shape="rect"]] which are not meant to work with a GUI (output to file).

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Software on Maxwell is managed via the Module system. So check

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module avail

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for all available software and

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(% class="code" %)

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moduel load *

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e.g

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module load matlab/R2019a

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to install the listed software.

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===== Access Points =====

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The most convenient and officially preferred way is via the [[Maxwell Display Server >>url:https://max-display3.desy.de:3389||shape="rect"]]via (% class="twikiNewLink" %)FastX2(%%) client or web browser. Required ressources will be automatically given to new {{code language="none"}}Scientific User Accounts{{/code}} and can be requested for existing accounts via FS-EC.

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[[Photon Science staff >>url:https://confluence.desy.de/display/IS/Maxwell+for+Photon+Science||shape="rect"]]can also connect to the work group server [[max-fsc.desy.de>>url:http://max-fsc.desy.de||shape="rect"]] or - if you need a GPU for your calculations - [[max-fsg.desy.de>>url:http://max-fsg.desy.de||shape="rect"]]. [[External Users>>url:https://confluence.desy.de/display/IS/Maxwell+for+Photon+Science+users||shape="rect"]] can also SSH to [[desy-ps-cpu.desy.de>>url:http://desy-ps-cpu.desy.de||shape="rect"]]{{code language="none"}}{{/code}} or - if you need a GPU for your calculations - [[desy-ps-gpu.desy.de>>url:http://desy-ps-gpu.desy.de||shape="rect"]] from inside the DESY network. From outside they have to connect to [[max-display.desy.de>>url:http://max-display.desy.de||shape="rect"]] first.

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For working with [[ Python>>doc:FLASHUSER.Data Acquisition and controls.Data Access at FLASH (DAQ, gpfs,\.\.\.).Online data analysis.Anaconda Python at FLASH.WebHome]]'s Jupyter Notebooks DESY provides a [[Jupyterhub~[~[image:url:http://hasfweb.desy.de/pub/TWiki/TWikiDocGraphics/external-link.gif~|~|width="13" height="12"~]~]>>url:https://confluence.desy.de/display/IS/JupyterHub+on+Maxwell||shape="rect"]] instance and its resource is automatically allocated to new Scientific User Accounts.

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===== During the beamtime =====

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For online processing during a beamtime it is possible to make a node reservation via maxwell(at)service, which have to be done 1 to 2 weeks before the beamtime. At the point when you start the beamtime in the [[GPFS>>url:https://confluence.desy.de/display/ASAP3/Directory+Structure||shape="rect"]] all user should have a [[DOOR>>url:https://door.desy.de/door/||shape="rect"]] account, be rgeistered as participants for the beamtime and have a scientific user account to work on this node. Currently (Mai 2019) FS could also provide a node with a single P100 GPU.

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===== Scientifc User Accounts =====

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For working at Maxwell you need the corresponding resources which the Scientific User Account. On Maxwell you can check the resources of a User via (passing the User's id is optional):

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my-resources id

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When you login in Maxwell the first time a home directory with a hard quota of 20 GB is created. By default Inhouse staff will be granted the PS-resource while external users will be granted the PSX-resource.

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To create a Scientific User Account the Local Contact have to request it via FS-EC while passing User's {{code language="none"}}Full Name{{/code}} and(% class="WYSIWYG_TT" %) E-mail Address(%%). FS-EC will send a form the User have to sign and after that the Local Contact gives the User (verbally) the initial password.

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===== SLURM scheduler =====

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Slurm is an open source resource management and job scheduling system for Linux clusters. It schedules via a "who comes first" basis, but is using a "back-fill algorithm".

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Job submission nodes are available via the load balancer: max-display, max-fsc & max-fsg.

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[[image:attach:slurm-job-submission.png||height="250"]]

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====== Example: Slurm Job Submission ======