Redirectorxrootd proxy mgr

Xrd proxydata server

N2NXrd proxydata server

N2N

Global Redirector

Client

Backend Xrootd

storage

0. Join the Federation

1. Open (GFN)2. Open (GFN)

3. Open/Read (GFN)

4. Read (PFN) Fetched data

data

Export Xrootd storage via Xrootd Proxy cluster

GFN: global file namePFN: physical (storage) file nameN2N: translation GFN to PFNcms.dfs directive: see

cms.dfs : all data servers are equal

http://www.xrootd.org/doc/prod/cms_config.htm#_Toc295744046

RedirectorXrootd mgr

Regluar Xrddata server

N2NRegular Xrddata server

N2N

Global Redirector

Client

Backend Posix

storage

0. Join the Federation

1. Open (GFN)2. Open (GFN)

3. Open/Read (GFN)

4. Read (PFN) Fetched data

data

Export Posix storage via regular Xrootd cluster

GFN: global file namePFN: physical (storage) file nameN2N: translation GFN to PFNPosix file system: GPFN, Luster, XrootdFS

cms.dfs : all data servers are equal

Posix File system Posix File system

RedirectorXrootd mgr

Regular Xrddata server with

N2NRegular Xrddata server with

N2N

Global Redirector

Client

Backend dCache

dCap doors

0. Join the Federation

1. Open (GFN)2. Open (GFN)

3. Open/Read (GFN)

4. Read (PFN) Fetched data

data

Export dCache dCap doors via regular Xrootd cluster

GFN: global file namePFN: physical (storage) file nameN2N: translation GFN to PFNdCap plugin: a Xrootd OFS plug-in moudel using dCap protocol

cms.dfs : all data servers are equal

dCap plug-in dCap plug-in

Redirectorxrootd proxy mgr

Xrd proxydata server

N2NXrd proxydata server

N2N

Global Redirector

Client

Backend dCache

Xrootd doors

0. Join the Federation

1. Open (GFN)2. Open (GFN)

3. Open/Read (GFN)

4. Read (PFN) Fetched data

data

Export dCache Xrootd doors via Xrootd Proxy cluster, 1

GFN: global file namePFN: physical (storage) file nameN2N: translation GFN to PFN

cms.dfs : all data servers are equal

Regular xrootddata server withXrootd.redirect …

Global Redirector

Client

0. Join the Federation

1. Open (GFN)2. Open (GFN)

data

Export dCache Xrootd doors via Xrootd Proxy cluster, 2

GFN: global file namePFN: physical (storage) file nameN2N: translation GFN to PFNFor Xrootd.redirect directive, see:

dCache pool node with Auth plug-in for N2N

dCache pool node with Auth plug-in for N2N

dCache xrootd doorAuth plug-in for N2N

3. Open (GFN)

4. Open/Read (GFN)

http://www.xrootd.org/doc/prod/xrd_config.htm#_Toc305602916

RedirectorXrootd mgr

Global Redirector

Client

0. Join the Federation

1. Open (GFN)2. Open (GFN)

3. Open/Read (GFN)

data

Overlapping Xrootd cluster on top of dCache

GFN: global file namePFN: physical (storage) file nameN2N: translation GFN to PFNGFN name space : native xrootd name space layout according to GFN, with symlinks pointing to actual file on the same node(some CMS sites do this)

dCache pool node

Native Xrootd data serverGFN name space (symlinks) or N2N

dCache pool node

Native Xrootd data serverGFN name space (symlinks) or N2N