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  • Accessing data from the Tier-2 dCache
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You can run fireworks (cmsShow) on your laptop or desktop machine and access data directly from our Tier-2 storage element.
Just put the prefix 'root://' in front of the LFN.


> cmsShow root://

To copy a single file from the Tier-2 storage element to your local machine (laptop or desktop) you can use the command xrdcp.
First you need to initialize your ROOT or CMSSW environment (run cmsenv).


> xrdcp root:// my.root

You will get a progress bar as the file downloads. You may also want to think about using the -R option, which allows you to recursively download a directory.
Please see the details at

If you are using ROOT, you can open files from our Tier-2 storage element just like you would any other file:


This returns a TFile object, and you can proceed normally.


Data access through AAA:

Check for file availability with:

> xrd existfile /store/myfile.root 

Direct access: ROOT and CMSSW PoolSource can open a remote file directly through AAA

> “root://” 

Make a local copy:

> xrdcp root:// /localpath/myfile.root 

For additional information see:

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