StoRM Product Team

Product

StoRM (StoRM web site) is a SRM service compliant with the standard SRM v2.2. It is able to manage any POSIX file systems supporting Access Control List (ACL) mechanism, including high performance storage systems based on cluster file system (such as GPFS from IBM and Lustre from Oracle/Sun Microsystems).

StoRM decouples the file system from the SRM service, in the sense that it does not incorporate the storage system but it just relies on it; in other words StoRM specifically provides only management functionalities. StoRM uses the underlying file system features in two ways:

1. FS is used as final enforcer of authorization information (allowing the use of native access to the file system by authorized users and applications, as explained below)
2. FS is used as a natural store and manager of namespace, that means that StoRM does not make use of a database to store the namespace of managed resources (files).

StoRM uses the authorization mechanism offered by the underlying file system (ACL) to allow local and direct access using the native POSIX protocol (i.e. “file://”). Applications using the standard POSIX operation without using external data access library (e.g. RFIO) are resulting in considerably benefit in terms of I/O throughput, mostly in presence of high performance cluster file systems. Anyway, StoRM supports as well as other non-standard Grid access protocols offered by data access libraries like RFIO. Currently the supported Data Access / Data transfer protocols are: “file://”, “rfio://”, “gsiftp://”, “root://”.

StoRM solution includes several components/services:

• !StoRM FrontEnd : exposes the service. This component is replicable to compose a cluster.
• !StoRM BackEnd : it is the core of StoRM service
• !StoRM info provider: provides the static and dynamic information about StoRM service and its status.
• Checksummer service, used to compute checksum upon requests.
• !DSI plugin for GridFTP, used to compute adler32 checksum “on the fly”, and store the result in an Extended Attribute of the file transferred.
• !SRM Client, a C++ implementation of standard SRM v2.2 client usable via command line

The StoRM PT belongs to Data Technical Area

Technical details

StoRM Service Reference Card

External dependencies

Members

• Riccardo Zappi (INFN)
• Michele Dibenedetto (INFN)
• Elisabetta Ronchieri (INFN) - unfunded
• Stefano Dalpra (INFN) - unfunded
• Cristina Aiftimiei (INFN)
• Sergio Traldi (INFN) - unfunded

-- RiccardoZappi - 09-Sep-2010