Tape Libraries and Servers

The tape library systems consist of (1) SONY PetaSite DMS-8800, (2) SONY PetaSite DMS-8400 and (3) two sets of SONY PetaSite DMS-8400 with PetaServe hierarchical storage system software. Tape library system (1) has a capacity of 25 TB and contains two DIR-1000 tape drives with a writing speed of 32 MB/s and nine DIR-1000M tape drives with a writing speed of 16 MB/s. The two 32-MB/s DIR-1000 and one 16-MB/s DIR-1000M drives are connected to the fast data transfer system and used to write online data. Six 16-MB/s DIR-1000M tape drives are each connected to six of seven computing servers and used for DST production. The remaining two drives are connected to a less powerful compute server (11CPU) and used for the backup of the system. Tape library system (2) has a capacity of 75 TB and contains 15 DTF tape drives with a data transfer speed of 12 MB/s. Attached on each computing server are two DTF drives. Each set of tape library system (3) can hold 25 TB of data. The PetaServe hierarchical storage system software functions as if all files were on a hard disk. The RAID system consists of six Gen5 (Strategy S-Series XL) storage servers. Five of the six Gen5 servers have 640 GB each and the 6 one 480GB. Each storage server has up to 8 independent SCSI host connections and therefore the disks are connected to 31 data servers and 11 work group servers. The data servers and the compute servers are integrated into Fujitsu Parallel Server AP3000 with a proprietary network, called AP-Net by Fujitsu Ltd. The network has a two-dimensional torus topology with the maximum point to point data transfer speed of 200 MB/s. For each sub-detector group and each core software group, a work group server has been allocated. The number of CPUs varies from 2 to 6 depending on the size of the group. Eight of twelve work group servers have 2 to 6 250-MHz ultra SPARC II CPUs and four sets of 6 167-MHz ultra SPARC CPUs. Each group server has a 40 or 80 GB RAID system described above. Users, who usually log in to these work group servers, develop and debug programs, and analyze data. In the RAID system the storage capacity of 1.36 TB, which is mounted on the data servers, serves as NFS disks and holds mini-DST data. The capacity of 1.12 TB is also mounted on the data servers and serves as NFS disks with migration using 50 TB capacity of tape library (3). All servers run Solaris 2.5.1 operating system. The group and computing servers run DCE/DFS (Distributed Computing Environment/Distributed File System) from IBM and LSF (Load Sharing Facility, www.platform.com) from Platform computing. The KEKB computing system described above was set up in January 1997 and has been running since. The system is on a lease contract that ends in January 2001. A new system will be installed to replace the current system.