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Last modified by flenners on 2025-06-24 16:56
From version 11.1
edited by greving
on 2021-10-26 11:23
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To version 12.1
edited by riedelmi
on 2021-11-27 15:12
Change comment: Extended the maxwell description

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1 -= {{id name="00-HowtologintoMaxwell-ShortVersion:"/}}**Short Version: ** =
1 +The DESY has a quite powerful compute cluster called the Maxwell cluster. The documentation can be found here [[https:~~/~~/confluence.desy.de/display/MXW/Maxwell+Cluster>>doc:MXW.Maxwell Cluster.WebHome||shape="rect"]], however as this can be confusing sometimes, we will try to condensate this to a step by step manual.
2 2  
3 -Terminal:
4 4  
5 -(% class="code" %)
6 -(((
7 -salloc ~-~-partition=psx ~-~-nodes=1 –-time=06:00:00
8 -\\(if you need gpu: (% class="bash plain" %){{code language="none"}}--constraint=P100{{/code}}(%%) )
9 -\\ssh max-bla123
10 -\\module load anaconda
11 -\\source activate ~~/envs/tomopy
12 -\\spyder&
13 -)))
14 14  
15 -\\
5 +{{toc/}}
16 16  
17 -\\
7 += {{id name="00-HowtologintoMaxwell-GettingaDESYAccount"/}}Getting a DESY Account =
18 18  
19 -{{code linenumbers="true" collapse="true"}}
20 -salloc --partition=psx --nodes=1 –-time=06:00:00
9 +During you beamtime you will encounter multiple systems, where you will need two different types of accounts:
21 21  
22 -ssh max-bla123
11 +== {{id name="00-HowtologintoMaxwell-TheDOORAccount"/}}The DOOR Account ==
23 23  
24 -module load anaconda
13 +Before you arrive you have to create a DOOR account (Institution: Physik Department E17) and do all the safety trainings. This account is also being used for the gamma-portal, where you can manage you beamtime data, grant access to other users and manage FTP access. However this account does not work with other resources. For this you will have to request a second account:
25 25  
26 -source activate ~/envs/tomopy
15 +== {{id name="00-HowtologintoMaxwell-ThePSXAccount"/}}The PSX Account ==
27 27  
28 -spyder&
17 +If you decide during a beamtime, you want to have access to the cluster, tell your local contact so, and they will request a PSX account for you. With this you will get access to the Kerberos, Windows and afs resources at DESY, which includes the cluster.
18 +
19 += {{id name="00-HowtologintoMaxwell-UsingtheCluster"/}}Using the Cluster =
20 +
21 +== {{id name="00-HowtologintoMaxwell-StructureoftheCluster"/}}Structure of the Cluster ==
22 +
23 +=== {{id name="00-HowtologintoMaxwell-Overview"/}}Overview ===
24 +
25 +The Maxwell Cluster has (status 2021) more than 750 nodes in it. To organize this, you cannot access any node directly, but you have to request compute resources at first. You then can connect form an entrance node to you compute node
26 +
27 +=== {{id name="00-HowtologintoMaxwell-EntranceNodes"/}}Entrance Nodes ===
28 +
29 +If you have successfully obtained an PSX account you can get started. The entrance node are:
30 +\\[[https:~~/~~/max-nova.desy.de:3443/auth/ssh>>url:https://max-nova.desy.de:3443/auth/ssh||shape="rect"]]  (if you have access to the nova resources, most likely the case if your beamtime was in cooperation with the Helmholtz Zentrum Hereon)
31 +
32 +[[https:~~/~~/max-display.desy.de:3443/auth/ssh>>url:https://max-display.desy.de:3443/auth/ssh||shape="rect"]]  (in any case)
33 +
34 +These nodes are **not **for processing, as you will share them with many other users. So please do not do anything computational intensive on them, like reconstruction or visualization. Viewing images is ok.
35 +
36 +=== {{id name="00-HowtologintoMaxwell-FastX2"/}}Fast X2 ===
37 +
38 +The cluster uses the software FastX2 for connection and virtual desktop. To get the right version of this, use the web interface, log in, and in the bottom right corner is a download link for the desktop client. The version has to match exactly to work properly.
39 +
40 +If you want to add a connection in the desktop client, click the plus, select web, use the address above (including the port), and your username and force ssh authentication. Then you can choose if you want a virtual desktop (XFCE) or a terminal.
41 +
42 +=== {{id name="00-HowtologintoMaxwell-Partitions"/}}Partitions ===
43 +
44 +Starting from an entrance node, you can connect to a compute node. As there are multiple levels of priorities etc. the nodes are organizes in partitions. You can only access some of these. To view which one, open a terminal and use the commad:
45 +
46 +{{code}}
47 +my-partitions
29 29  {{/code}}
30 30  
50 +Your result will look something like this:
51 +
52 +[[image:attach:P5I.User Guide\: NanoCT.4\. Reconstruction Guide.00 - How to login to Maxwell.WebHome@image2021-5-4_10-28-14.png||queryString="version=1&modificationDate=1620116894626&api=v2" alt="image2021-5-4_10-28-14.png"]]
53 +
54 +== {{id name="00-HowtologintoMaxwell-SLURM"/}}SLURM ==
55 +
56 +The access to the resources of the cluster is managed via a scheduler, SLURM.
57 +
58 +SLURM schedules the access to nodes and can revokes access if higher priority jobs come.
59 +
60 +=== {{id name="00-HowtologintoMaxwell-PSXPartition"/}}PSX Partition ===
61 +
62 +Here you cannot be kicked out of your allocation. However, only few nodes are in this partition and you can also only allocate few in parallel (2021: 5). Some of them have GPUs available.
63 +
64 +=== {{id name="00-HowtologintoMaxwell-AllPartition"/}}All Partition ===
65 +
66 +Very large number of nodes available and you can allocate many in parallel (2021: 100). However each allocation can be revoked without a warning if s.o. with higher priority comes. This is very common to happen. If you want to use this partition, be sure to design your job accordingly. Only CPU nodes.
67 +
68 +=== {{id name="00-HowtologintoMaxwell-AllgpuPartition"/}}Allgpu Partition ===
69 +
70 +Like all, but with GPUs
71 +
72 +=== {{id name="00-HowtologintoMaxwell-JhubPartition"/}}Jhub Partition ===
73 +
74 +For Jupyter Hub
75 +
76 +See also the section on python.
77 +
78 +=== {{id name="00-HowtologintoMaxwell-HzgPartition"/}}Hzg Partition ===
79 +
80 +Ask someone from hereon how to use them (e.g. [[Riedel, Mirko>>url:https://wiki.tum.de/display/~~ga78nig||shape="rect"]] )
81 +
31 31  \\
32 32  
33 -Spyder:
84 +== {{id name="00-HowtologintoMaxwell-ConnectingtotheCluster"/}}Connecting to the Cluster ==
34 34  
35 -Open RecoGUI,
86 +Connect to an entrance node via FastX. You will automatically be assigned to a node when you start a session via a load balancer (max-display001-003, max-nova001-002)
36 36  
37 -(Right click on tab: "Set console working directory") (to be removed)
88 +[[image:attach:P5I.User Guide\: NanoCT.4\. Reconstruction Guide.00 - How to login to Maxwell.WebHome@image2021-4-27_13-55-52.png||queryString="version=1&modificationDate=1619524552546&api=v2" alt="image2021-4-27_13-55-52.png"]]
38 38  
39 -Green Arrow to start program
90 +Choose a graphic interface and look around.
40 40  
41 41  \\
42 42  
43 -= {{id name="00-HowtologintoMaxwell-LongVersion:"/}}**Long Version: ** =
94 +== {{id name="00-HowtologintoMaxwell-DataStorage"/}}Data Storage ==
44 44  
96 +The Maxwell cluster knows many storage systems. The most important are:
97 +
98 +Your User Folder: This has a hard limit of 30 GB. Be sure not to exceed this.
99 +
100 +The GPFS: here all the beamtime data are stored.
101 +
102 +=== {{id name="00-HowtologintoMaxwell-GPFS"/}}GPFS ===
103 +
104 +Usually you can find you data at: /asap3/petra3/gpfs/<beamline>/<year>/data/<beamtime_id>
105 +
106 +In there you will find a substructure:
107 +
108 +* raw: raw measurement data. Only applicant and beamtime leader can write/delete there
109 +* processed: for all processed data
110 +* scratch_cc: scratch folder w/o backup
111 +* shared: for everything else
112 +
113 +The GPFS has regular snapshots. The whole capacity of this is huge (several PB)
114 +
115 +== {{id name="00-HowtologintoMaxwell-HowtoGetaComputeNode"/}}How to Get a Compute Node ==
116 +
117 +If you want to do some processing, there are two ways to start a job in SLURM:
118 +
119 +1. Interactive
120 +1. Batch
121 +
122 +In both cases you are the only person working on the node, so use it as much as you like.
123 +
124 +=== {{id name="00-HowtologintoMaxwell-StartinganInteractiveJob"/}}Starting an Interactive Job ===
125 +
126 +To get a node you have to allocate one via SLURM e.g. use:
127 +
128 +{{code}}
129 +salloc -N 1 -p psx -t 1-05:00:00
130 +{{/code}}
131 +
132 +Looking at the individual options:
133 +
134 +* salloc: specifies you want a live allocation
135 +* -N 1: for one node
136 +* -p psx: on the psx partition. You can also add multiple separated with a comma: -p psx,all
137 +* -t 1-05:00:00: for the duration of 1 day and 5h
138 +* Other options could be: ~-~-mem=500GB with at least 500GB of memory
139 +* ... see the SLURM documentation for more options
140 +
141 +If your job is scheduled you see your assigned node and can connect via ssh to it. (in the rare case where you do not see anything use my-jobs to find out the host name).
142 +
143 +=== {{id name="00-HowtologintoMaxwell-Startingabatchjob"/}}Starting a batch job ===
144 +
145 +For a batch job you need a small shell script describing what you want to do. You do not see the job directly, but the output is written to a log file (and results can be stored on disk)
146 +
147 +With a batch job, you can also start an array job, where the same task is executed on multiple servers in parallel.
148 +
149 +An example for such a script:
150 +
151 +{{code}}
152 +#!/bin/bash
153 +#SBATCH --time 0-01:00:00
154 +#SBATCH --nodes 1
155 +#SBATCH --partition all,ps
156 +#SBATCH --array 1-80
157 +#SBATCH --mem 250GB
158 +#SBATCH --job-name ExampleScript
159 +
160 +
161 +source /etc/profile.d/modules.sh
162 +echo "SLURM_JOB_ID $SLURM_JOB_ID"
163 +echo "SLURM_ARRAY_JOB_ID $SLURM_ARRAY_JOB_ID"
164 +echo "SLURM_ARRAY_TASK_ID $SLURM_ARRAY_TASK_ID"
165 +echo "SLURM_ARRAY_TASK_COUNT $SLURM_ARRAY_TASK_COUNT"
166 +echo "SLURM_ARRAY_TASK_MAX $SLURM_ARRAY_TASK_MAX"
167 +echo "SLURM_ARRAY_TASK_MIN $SLURM_ARRAY_TASK_MIN"
168 +
169 +module load maxwell gcc/8.2
170 +
171 +.local/bin/ipython3 --pylab=qt5 PathToYourScript/Script.py $SLURM_ARRAY_TASK_ID
172 +
173 +exit
174 +
175 +
176 +{{/code}}
177 +
45 45  \\
46 46  
47 -**Login to max-nova**: E.g. from browser [[https:~~/~~/max-nova.desy.de:3443/>>url:https://max-nova.desy.de:3443/auth/ssh||shape="rect"]]
180 +To run this use
48 48  
182 +{{code}}
183 +sbatch ./your_script.sh
184 +{{/code}}
185 +
49 49  \\
50 50  
51 -Click on "**Launch Session**" and "**XFCE**" Icon
188 +=== {{id name="00-HowtologintoMaxwell-Viewingyouallocations"/}}Viewing you allocations ===
52 52  
53 -[[image:attach:image2021-4-27_13-55-52.png||height="250"]]
190 +To view your pending or running allocations you can use:
54 54  
192 +{{code}}
193 +squeue -u <username>
194 +
195 +or
196 +
197 +my-jobs
198 +{{/code}}
199 +
55 55  \\
56 56  
57 -**Open a Terminal**, e.g. from the icon at the bottom of your desktop. You can also open it via right click → "Open Terminal here" directly on your desktop or from any folder.
202 +=== {{id name="00-HowtologintoMaxwell-Whatisrealisticintermsofresources"/}}What is realistic in terms of resources ===
58 58  
59 -[[image:attach:image2021-4-27_13-58-35.png||height="250"]]
204 +To be fair, you will not get 100 nodes every time you want them. Especially during a user run, the machines are often quite busy. But if you design your scripts to be tolerant to sudden cancellation, it is still worth trying if you profit from massive parallelization.
60 60  
206 +If you want to do some small processing, use one of the psx nodes. This should work most of the time.
207 +
61 61  \\
62 62  
63 -Now you can **allocate a node** for yourself, so you will have enough memory and power for your reconstruction.
210 +== {{id name="00-HowtologintoMaxwell-GrantingDataAccesstootherBeamtimes"/}}Granting Data Access to other Beamtimes ==
64 64  
212 +If you have to add other users to a past beamtime, this can be done via the gamma-portal. After adding the accounts, these people have to make sure to log off from **all **FastX sessions, etc. to update the permissions.
213 +
214 += {{id name="00-HowtologintoMaxwell-StartingarecoGUI"/}}Starting a reco GUI =
215 +
216 +== {{id name="00-HowtologintoMaxwell-ShortVersion:"/}}Short Version: ==
217 +
218 +Terminal:
219 +
65 65  (% class="code" %)
66 66  (((
67 -salloc ~-~-partition=psx ~-~-nodes=1 ~-~-time=06:00:00
222 +salloc ~-~-partition=psx ~-~-nodes=1 –-time=06:00:00
223 +\\(if you need gpu: (% class="bash plain" %){{code language="none"}}--constraint=P100{{/code}}(%%) )
224 +\\ssh max-bla123
225 +\\module load anaconda
226 +\\source activate ~~/envs/tomopy
227 +\\spyder&
68 68  )))
69 69  
70 70  \\
71 71  
72 -You will get a node for 6 hours, you can also choose longer or shorter times.
232 +\\
73 73  
74 -It can take some time before you get a node, then it will tell you which node is reserved for you. (Example: max-exfl069)
234 +{{code linenumbers="true" collapse="true"}}
235 +salloc --partition=psx --nodes=1 –-time=06:00:00
75 75  
76 -\\
237 +ssh max-bla123
77 77  
78 -Now you can  **login via ssh** on this node:
239 +module load anaconda
79 79  
80 -(% class="code" %)
81 -(((
82 -ssh max-exfl069
83 -)))
241 +source activate ~/envs/tomopy
84 84  
85 -Enter your password.
243 +spyder&
244 +{{/code}}
86 86  
87 87  \\
88 88  
89 -EXAMPLE:
248 +Spyder:
90 90  
91 -[[image:attach:image2021-4-27_13-52-11.png||height="125"]]
250 +Open RecoGUI,
92 92  
93 -Hint: Please use partition=psx, if you use =all, the connection might close while you are working if someone with higher priority needs the node you are working on.
252 +(Right click on tab: "Set console working directory") (to be removed)
94 94  
254 +Green Arrow to start program
255 +
95 95  \\
96 96  
97 -Now you are on a different node [[image:http://confluence.desy.de/s/de_DE/7901/4635873c8e185dc5df37b4e2487dfbef570b5e2c/_/images/icons/emoticons/smile.svg||title="(Lächeln)" border="0" class="emoticon emoticon-smile"]].
258 +== {{id name="00-HowtologintoMaxwell-LongerVersion"/}}Longer Version ==
98 98  
99 99  \\
100 100  
262 +Login to maxwell and allocate a node from the psx partition.
263 +
264 +\\
265 +
101 101  You first have to **load the anaconda module:**
102 102  
103 103  (% class="code" %)
... ... @@ -138,23 +138,4 @@
138 138  
139 139  \\
140 140  
141 -Hint: You can check your partition via
142 -
143 -(% class="code" %)
144 -(((
145 -my-partitions
146 -)))
147 -
148 -You should have access to psx.
149 -
150 -[[image:attach:image2021-5-4_10-28-14.png]]
151 -
152 152  \\
153 -
154 -For further information also check:
155 -
156 -[[doc:IS.Maxwell.WebHome]]
157 -
158 -\\
159 -
160 -\\
Confluence.Code.ConfluencePageClass[0]
Id
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1 -235027533
1 +235027534
URL
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1 -https://confluence.desy.de/spaces/P5I/pages/235027533/02 - How to login to Maxwell and start RecoGUI
1 +https://confluence.desy.de/spaces/P5I/pages/235027534/02 - How to login to Maxwell and start RecoGUI