#+TITLE:   2012/02/23 Rucio Meeting on Rucio Storage Elements
#+PRESENT: Armin, Vincent, Angelos, Martin, Thomas, Luis, Mario

* What is an Rucio Storage Element (RSE)?
** Two opinions:
*** A) RSE is what now is a Space-Token (Endpoint) in ToA
*** B) RSE is a real, physical storage system (like CERN EOS, or CERN CASTOR)

* Option B)
** Typical CERN RSE's would be:   
   CERN_EOS
   CERN_CASTOR_DISK
   CERN_CASTOR_TAPE
** Problem with the logical partition of the space (a.k.a.) Spacetokens
   Currently a storage system is logically partitioned into sub-spaces
   /mcdisk
   /datadisk
   /userdisk
   /scratchdisk
** Do we need a separation like this in Rucio? e.g. for each RSE there exists a set of prefixes
   The current logical partioning of the space was done because of a lack of proper accounting
   So maybe we do not need this anymore?
*** Problem with prefixes = the actual identifier of storage-space would consists of RSE+prefix
** Each RSE consists of a set of services as well (SRM, FTS, HTTP, ...)
   |----------+-----------------+------+-------+-------------|
   | Protocol | hostname        | port | async | localaccess |
   |----------+-----------------+------+-------+-------------|
   | SRM      | srm.eos.cern.ch |      | No    |             |
   | FTS      |                 |      |       |             |
   | HTTP     |                 |      |       |             |
   | HTTP     |                 |      |       |             |
   | file     |                 |      |       |             |
*** Problem: For FTS there is actually a distinction of using specific servers for src/dst combinations
**** Should this be represented in the information system or handled as a special case?

* RSE-TAGS
** Typical RSE Tags:
   CERN = [ CERN_EOS, CERN_CASTOR_DISK, CERN_CASTOR_TAPE ]
   CERN_DISK = [ CERN_EOS, CERN_CASTOR_DISK ]
   CH_CLOUD = [ CERN, ... ]
   etc.
** Do we actually need a K/V approach here
   e.g. to store contact adresses of CLOUD representatives etc.?
