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Incremental Scalability
Based on storage needs and deployment schedules, HPSS scales incrementally by adding computer, network and storage resources. A single HPSS namespace can scale from petabytes of data to exabytes of data, from millions of files to billions of files, and from a few file-creates per second to thousands of file-creates per second.
About HPSS   :    HPSS RAIT Technology
What is HPSS RAIT?

HPSS RAIT (Redundant Array of Independent Tapes) is an HPSS software technology for striping data on tape with the added benefit of parity for redundancy. HPSS RAIT with single parity is similar to RAID-5 and HPSS RAIT with two parities is similar to RAID-6, except HPSS RAIT is used with tape. HPSS with RAIT still streams the tape drives at hardware speed, and stripe widths of up to 16 (data+parity) are available.

HPSS RAIT is transparent to the client using any of the existing HPSS client interfaces: FUSE, SwiftOnHPSS, FTP, Parallel FTP, HSI, HTAR, and other third-party HPSS client applications.

Why use HPSS RAIT?

HPSS RAIT offers two main advantages. First, RAIT allows data to flow to and from tape in a parallel manner. Parallel tape I/O allows single file transfers to exceed the native transfer rate of a single tape drive. At Oak Ridge National Laboratory (ORNL), large file I/O exceeds 1 GB/s with their 4+P HPSS RAIT stripe deployed on 250 MB/s tape technology. Thus, a 1 TB file can be written to tape in less than 17 minutes. Without parallel I/O, a 1 TB file might take over an hour to transfer using a single 250 MB/s tape drive.

Additionally, when compared to dual-copy tape, HPSS RAIT lowers redundant tape costs. At the lowest level, a 2+P HPSS RAIT will deliver up to 2x improvement in tape bandwidth and typically cuts the cost of redundant tape by 45%. Redundant tape costs are cut by 45%, rather than 50%, because typically 90% of the files by count only take 10% of the space in an HPSS repository, while 10% of the files by count take up 90% of the space. HPSS RAIT is intended for large files, so for greater recall efficiency, dual-copy tape is used to protect smaller files.

There are two basic methods of redundancy: making multiple copies (mirroring), and redundancy through error-correcting codes (such as Reed-Solomon). RAIT uses Reed-Solomon error-correcting codes which are less expensive than making multiple copies due to the lower tape, drive, space, and power requirements.

The Value of RAIT over Mirroring

There is a lower cost of fault tolerance with RAIT: fewer tape drives and cartridges are required. There are also faster mount times when compared with writing to a mirrored volume. For example, in the case of an 8 tape stripe and adding single failure redundancy: mirroring would require 8 additional tapes, resulting in a total of 16 tapes. RAIT, however, would only need 1 extra tape, resulting in a total of 9 tapes to accomplish the redundancy.

There is a high tolerance for tape loss within the HPSS RAIT stripe. RAIT reads and RAIT writes will continue even if there is a tape mount or tape media error. Automatic data recovery takes place during the RAIT read operation because HPSS can reconstruct the missing data using the parity and surviving data blocks.

What's Under the Hood of HPSS RAIT?

At the heart of HPSS RAIT is the HPSS RAIT engine. Client data will automatically flow through the HPSS RAIT engine for all HPSS RAIT transfers to and from tape.

Like HPSS' RAID counterparts, the HPSS RAIT parity rotates across all tapes in the RAIT stripe. Rotating the parity evens out the compressibility of the data on tape by ensuring an equal amount of data and parity are written to each tape cartridge.

The figure below illustrates a single HPSS RAIT engine accepts four data blocks (A, B, C, and D) at a time from the client, generate the two parity blocks (P and Q), and send the six data blocks to tape in a parallel manner. Notice that the figure illustrates how the "File Data Block" is processed in four iterations, as follows:

1. A1, B1, C1, and D1 + P1 and Q1

2. A2, B2, C2, and D2 + P2 and Q2

3. A3, B3, C3, and D3 + P3 and Q3

4. A4, B4, C4, and D4 + P4 and Q4

The following illustration shows how data movement occurs:

HPSS RAIT Write Operations

HPSS RAIT Configuration Options and Features

  • HPSS RAIT supports data stripe width of up to 15 and a parity stripe width of up to 7.
  • You can control whether to mount the entire RAIT volume or only a minimal set of tapes for reading from a RAIT volume. For an 8 data/3 parity volume, this would cause 9 tapes to be mounted rather than 11 if the data is being verified against parity.
  • Read verification allows users to verify that the data being read still matches the parity, with stripe-level data integrity.

Proven in the Field

ORNL:
  • ORNL began using HPSS RAIT in January 2015, and are seeing faster tape mounts when compared to writing a mirror.
  • ORNL was able to cut redundant tape cost-estimates by 75% with 4+Parity HPSS RAIT (tape stripe with rotating parity) and enjoy large file tape transfers beyond 1 GB/s.

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Come meet with us!
HPSS @ STS 2021
The 3nd Annual Storage Technology Showcase is in the planning stage, but HPSS expects to support the event in March of 2021. Check out their web site - Learn More. We expect an update later in 2020.

HPSS @ ISC21
The 2021 international conference for high performance computing, networking, and storage will be in Frankfurt, Germany from June 27th through July 1st, 2021 - Learn More. Come visit the HPSS folks at the IBM booth and contact us if you would like to schedule a face-to-face meeting with us in Frankfurt.

2021 HUF
The 2021 HPSS User Forum (HUF) is being hosted by Karlsruhe Institute of Technology (KIT) in Karlsruhe, Germany from September 27th through September 30th, 2021. This is a great place to meet HPSS users, collaboration developers and testers (from IBM and DOE Labs), support folks, and leadership. More details coming soon.

HPSS @ SC21 - VIRTUAL
The 2021 international conference for high performance computing, networking, storage and analysis will be in St. Louis, MO from November 15th through 18th, 2021 - Learn More. As we do each year, we are scheduling and meeting with customers via IBM Single Client Briefings. Please contact your local IBM client executive or contact us to schedule a HPSS Single Client Briefing to meet with the IBM business and technical leaders of HPSS.

What's New?
Atos Press Release - Atos boosts Météo-France’s data storage capacity to over 1 exabyte in 2025 to improve numerical modeling and climate predictions. Want to read more?

HUF 2020 - The HPSS User Forum was hosted virtually at no cost in October 2020.

HPSS 9.1 Release - HPSS 9.1 was released on September 24th, 2020 and introduces a few new features.

HPSS 8.3 Release - HPSS 8.3 was released on March 31st, 2020 and introduces one new feature and many minor changes.

HPSS 8.2 Release - HPSS 8.2 was released on December 6th, 2019 and introduces a few new features.

New Globus DSI - Version 2.9 of the HPSS DSI is now available from the GitHub release page. It provides the capability to resume interrupted Globus transfers.

Lots Of Data - In November 2019 IBM/HPSS delivered a system to a customer in Canada and demonstrated a sustained tape ingest rate of 11,574 MB/sec (1 PB/day peak tape ingest) while simultaneously demonstrating a sustained tape recall rate of 8,832 MB/sec (791 TB/day peak tape recall). HPSS pushed four 13-frame IBM TS4500 tape libraries (scheduled to house over 500 PB of tape media) to 2,168 mounts/hour.

HPSS 8.1 Release - HPSS 8.1 was released on October 1st, 2019 and introduces a few new features.

July 2019 - Argonne Team Breaks Record for Globus Data Movement from the Summit supercomputer at Oak Ridge National Laboratory to HPSS tape.

Capacity Leader - ECMWF (European Center for Medium-Range Weather Forecasts) has a single HPSS namespace with over 556 PB spanning over 405 million files.

File-Count Leader - LLNL (Lawrence Livermore National Laboratory) has a single HPSS namespace with over 63 PB spanning 1.525 billion files.

Explosive data growth - HPSS Collaboration leadership from Lawrence Berkeley National Laboratory's National Energy Research Scientific Computing Center (NERSC) helped author the "NERSC Storage 2020" report, and NERSC trusts HPSS to meet their immediate and long term data storage challenges.

Older News - Want to read more?
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