Speaker
T. Mkrtchyan
(DESY)
Description
After successful implementation and deployment of the dCache system
over the last years, one of the additional required services, the
namespace service, is faced additional and completely new
requirements. Most of these are caused by scaling the system, the
integration with Grid services and the need for redundant (high
availability) configurations. The existing system, having only an
NFSv2 access path, is easy to understand and well accepted by the
users. This single 'access path' limits data management task to make
use of classical tools like 'find', 'ls' and others. This is intuitiv
for most users, but failed while dealing with millions of entries
(files) and more sophisticated organizational schemes (metadata). The
new system should support a native programmable interface (deep
coupled, but fast), the 'classical' NFS path (now version 3 at
least),
a dCache native access and the SQL path allowing any type of metadata
to be used in complex queries. Extensions with other 'access paths'
will be possible. Based on the experience with the current system we
highlight on the following requirements:
- large file support (64 Bit) + large number of files (> 10^8)
- fast
- Platform independents (runtime + persistent objects)
- Grid name service integration
- custom dCache integration
- redundant, high available runtime configurations (concurrent
backup etc.)
- user usable metadata (store and query)
- ACL support
- pluggable authentication (e.g. GSSAPI)
- external processes can register for namespace events (e.g.
removal/creation of
files
The presentation will show a detailed analysis of the requirements,
the choosen design and selection of existing components. The current
schedule should allow to show the first prototype results.
