Use of SONY PetaSite and DTF Helical Scan Tape Drive on KEK Central Computer UNIX Cluster

Paper: 300
Session: C (poster)
Presenter: Morita, Youhei, KEK, Tsukuba
Keywords: data management, hierarchical storage management, large systems, mass storage

Use of SONY PetaSite and DTF Helical Scan Tape Drive
on KEK Central Computer UNIX Cluster

Youhei Morita, Shigeo Yashiro, Junsei Chiba
National Laboratory for High Energy Physics (KEK)
1-1 Oho, Tsukuba, Ibaraki 305 Japan

Yutaka Kodama, Shunji Kohno, Nobuyuki Tanaka
Government & Public Corporation
Information Systems Division,
HITACHI, Ltd., Computer Group
Tsukuba Mitsui bldg. 1-6-1,
Takezono, Tsukuba, Ibaraki 305 Japan


A SONY PetaSite mass storage system is being used at KEK Central
Computer UNIX workgroup cluster since January 1996. This hierarchical
mass storage system has a total storage capacity of 20 TB, and twenty
SONY DTF helical scan tape drives, each drive has I/O throughput speed
of 12 MB/sec, are connected to several workstation workgroup clusters.

Extensive amount of HEP experiment data requires large storage space
as well as high speed I/O throughput between the storage media and the
CPU. To utilize the DTF tape drive at its highest throughput, about
half of the drives are attached to "Computation Server", where users
record, read out and analyze their data directly off the tape. The
rest of the tape drives are attached to the OmniStorage HSM server,
and is accessible via OSF DCE/DFS services.

Since UNIX raw devices does not provide a mechanism for users to
allocate or deallocate any tape drives, we have developed a "direct
access" tape library system. This system allows users to allocate and
deallocate tape drives, mount and unmount tape volumes automatically,
read and write the files sequentially, catalog the user file
information, and monitor the drive allocation status of other users.
It shares the volume management information with the OmniStorage HSM
server using a tape catalog information protocol, and the tape volume
management can be shared across several workgroup clusters. It also
allows the group permission for drive allocation and tape mounting so
that any member of a user group can inherit the environment of data
analysis production jobs from the previous user.

This system is being used by several fixed target experiment groups at
the KEK Proton Synchrotron for their data logging and analysis. In
this report, we present the system design and the performance of the
direct access tape library system as opposed to the off-the-shelf HSM