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ATLAS resources federation

* Zoom link: https://ethz.zoom.us/j/91556179990

Plan to federate two ATLAS sites into one.

CSCS-LCG2 (dCache), UNIBE-LHEP (DPM) => CHIPP-CH (DPM)

Note: the CSCS storage will physically remain at CSCS

Step 1 storage:

• Drain internally one dCache "storage unit" at CSCS, re-install it as a DPM "storage unit" and attach it to the Bern DPM head node
• Operate in this mode for a minimum of 6-8 weeks
• If no blocking issues are discovered: transition all storage pools from dCache to the DPM head node in Bern.
• Strategy to define, but can hope to drain and re-install as DPM (most of) them one by one internally if possible (to reduce load on DDM ops). This will shrink the size of the CSCS storage and increase that of the Bern storage.
• At some point during this procedure, move CSCS Panda queues to the Bern storage
• Make CSCS storage RO and finalise its draining and pool transition to the Bern storage

Step 2 create the new ATLAS site:

• Transition the Bern DPM endpoints to the new site

Step 3 Panda queues

• Move the Panda sites CSCS-LCG2 and UNIBE-LHEP (or create new ones) to the ATLAS site CHIPP-CH

Technical meeting with the following goals:

• Understand the Federation layout

• Swiss-ATLAS-Federation-layout.pdf: Swiss ATLAS Federation layout

• Understand CSCS storage layout for dCache and how to map it to DPM

• Understand the network layout between the two sites

• https://traffic.lan.switch.ch/vip/swiss-map/index.html
  
  
• Direct link with 100G capacity. Currently limited at 40G at the Bern border
  
  
• SE to SE path:

  [root@dpm ~]# traceroute se33.cscs.ch
  traceroute to se33.cscs.ch (148.187.19.183), 30 hops max, 60 byte packets
   1  beethoven-67.unibe.ch (130.92.67.1)  0.342 ms  0.876 ms  0.276 ms
   2  castorfw-inside.unibe.ch (130.92.0.36)  0.825 ms  0.815 ms  0.849 ms
   3  castor-inside.unibe.ch (130.92.244.3)  1.008 ms  0.997 ms  1.366 ms
   4  swiBE3-40GE-0-1-0-0-0.switch.ch (195.176.3.1)  1.317 ms  1.305 ms  1.254 ms
   5  swiLG1-100GE-0-0-0-3.switch.ch (130.59.36.102)  4.201 ms  4.200 ms  4.157 ms
   6  100G-C-IPv4.cscs.ch (148.187.0.10)  5.976 ms  3.717 ms  3.782 ms
   7  se33.cscs.ch (148.187.19.183)  3.542 ms  3.509 ms  3.306 ms

• SE to CE path (probably behind firewall):
  

  [root@dpm ~]# traceroute arc04.lcg.cscs.ch
  traceroute to arc04.lcg.cscs.ch (148.187.19.136), 30 hops max, 60 byte packets
   1  beethoven-67.unibe.ch (130.92.67.1)  0.317 ms  0.310 ms  0.271 ms
   2  castorfw-inside.unibe.ch (130.92.0.36)  0.830 ms  0.831 ms  0.930 ms
   3  castor-inside.unibe.ch (130.92.244.3)  1.464 ms  1.551 ms  1.527 ms
   4  swiBE3-40GE-0-1-0-0-0.switch.ch (195.176.3.1)  1.110 ms  1.547 ms  1.049 ms
   5  swiLG1-100GE-0-0-0-3.switch.ch (130.59.36.102)  4.303 ms  4.297 ms  4.271 ms
   6  * * *

• Work in progress: move Bern ARC CEs and SE nodes in DMZ

• Understand current network rates and data paths to/from dCache at CSCS

• Plan concretely the first step

• Lay a tentative plan out for the following step

• AOB