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EOS

This is a new xrootd based storage system at CERN. It is currently under test by CMS. While it will be left running over Christmas there will be very little support for it. It has been set up with aim of needing minimal maintenance. Users will be added to the cms-eos-users e-group to aid in communication.

Datasets Present

The T2_CH_CERN site in PhEDEx controls the data available.

Writing user output to space

For testing a directory to write output on the EOS system can be created.

If you have output you want to store back on to EOS you can use the cmsStage command;

cmsRun ... # produces a file
cmsStage myNtuple /store/eos/user/<HNusername>/

You can see that the prefix /eos/cms is used before LFNs with these eoscms commands. This is equivalent to the CASTOR namespace where it prefixed LFNs with /castor/cern.ch/cms.

You can check to see which files you have stored with;

eoscms ls /eos/cms/store/eos/user/<HNusername>/

For redundancy there are two copies of each file kept. There is space for 5TB of user output.

Proposed Migration Plan

Pool Current Size Proposed Size Proposed Date Prerequisites LFN Area #files Status
CMSCAF 1.7PB 2PB June 20-27 Switch to xrootd access (28th March), PhEDEx node T2_CH_CERN /store/ 992948 Done
CMSCAFUSER [*] 210TB 300TB September Data only under /store/caf/, CRAB stageout /store/caf/ 810051  
GRIDHOME [*] 50TB 100TB September Users need to update their CRAB config, redirect rule needed /store/user/ 13158  
CMSCAFT2 [*] 80TB 300TB September Redirect rule can be removed, CRAB stageout /store/user/ 22919  
DEFAULT 220TB 600TB September Dataset Popularity Service? /store/ 562143  
CMST3 [*] 420TB 420TB [1] September Users need to update their CRAB config, data only under /store/cmst3/, CRAB stageout /store/cmst3/ 1430045  
T0EXPRESS [*] 200TB 200TB November Tier-0 supports stage-out to xrootd /store/express/ 1762192  
T0TEMP 150TB 150TB November Tier-0 supports stage-out to xrootd /store/t0temp/ 373100  
T0STREAMER [2] 500TB 500TB ? P5 transfer supports stage-out to xrootd /store/t0streamer/ 9774998  

[*] These pools store only copy of data, perhaps replication factor should be 3, or a backup should be made
[1] There is a request to make this bigger but this isn't CMS space
[2] Not sure we want to move this pool as it should be phased out at some point and the use folded into t0temp space

We would still keep a small (100TB) DEFAULT pool on CASTOR till end of August. After that we can remove the redirect from EOS to CASTOR. Users would need to follow specific instructions to retrieve files from tape. Open question: what about /castor/cern.ch/user files?

-- StephenJGowdy - 15-Dec-2010

Topic attachments
I Attachment History Action Size Date Who Comment
Texttxt HIAZRAW.txt r1 manage 1288.6 K 2011-02-15 - 11:42 StephenJGowdy RAW ZS data on EOS
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Topic revision: r24 - 2011-09-03 - StephenJGowdy
 
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