Logical storage units in VOSpace 1.1
mjg at cacr.caltech.edu
Mon Aug 13 11:32:08 PDT 2007
A request has from our friends at SDSC to include references to the
actual storage units that data is being deposited on. The use case is
data replication so, for example, I want to move/copy a data object from
a slow tape archive to an ultrafast disk but both hardware units are
within the same VOSpace or I want to retrieve a data object from the
ultrafast disk copy and not the slow tape one.
I think that we can incorporate this easily into our existing data
model. We will refer to hardware units as logical storage units with the
implication that they are identified via a logical identifier (URI) that
is set by the particular VOSpace implementation. To get the list of
available storage units from a VOSpace, we will need a method:
getLogicalStorageUnits() which will return a list of URIs. These URIs
may be resolvable to a description of the storage unit.
The logical storage unit identifier will be an optional argument in the
<transfer> entity so that as part of the data transfer negotiation, the
user can specify a list of storage units that they want the data
transferred to/from. The identifier will also be an optional argument in
the <node> entity so that specific hardware can be targetted in moving
and copying data.
Comments, suggestions, etc.
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