StorageTek
SL8500 Robotic Tape Library

In late 2006, ARSC upgraded its storage systems. The Powderhorn tape silos were replaced by a Sun StorageTek SL8500 robotic tape library. Additional tapes were added in 2008 increasing the potential capacity beyond 7 petabytes.

Specifications

• Capable of storing over 7000 TB (terabytes) of data
• Eight independent Handbots™ travel on four rails (at up to 2.5 meters per second) for high performance data retrieval and redundancy
• An integrated service bay allows uninterrupted data access while typical maintenance tasks are performed

Description

The Arctic Region Supercomputing Center operates a StorageTek automated tape cartridge system for storage of users' data. The Storage and Archive Management (SAM) software provides semi-transparent access to the data. SAM automatically copies all user files on the storage servers to tapes in the tape library. Once copies are made on tape, SAM maintains adequate free disk space by releasing less-recently-used data blocks from disk. If a file whose data blocks only reside on tape is opened, SAM automatically mounts the appropriate tape and restores the data to disk.

Within the library, tape cartridges are manipulated by redundant, high-performance Handbots™. Tape cartridges have both barcodes read by scanners and numbered labels for manual manipulation when necessary. Some of the tapes also have RFID chips that identify them to the Handbots™.

Access time to a file on a tape consists of the time taken to retrieve and load the tape cartridge into a tape drive (about 10 seconds) and the time required to locate the file on the tape (up to 120 seconds, depending upon where on the tape the file is located) for an average response time of about a minute.

Under this system, effectively unlimited library space appears to the user as a seamless extension of disk space.

 

Arctic Region Supercomputing Center
PO Box 756020, Fairbanks, AK 99775 | voice: 907-450-8600 | email:

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