zHyperLink for the IBM Storage DS8000 (10th Generation) overview

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zHyperLink works with a fiber connectivity (FICON®) point-to-point or SAN infrastructure to provide low latency connectivity to FICON storage systems.

zHyperLink is a short distance, mainframe-attached link that provides up to 10 times lower latency than high-performance FICON. zHyperLink is intended to speed up Db2® for z/OS® transaction processing and improve active log throughput. zHyperLink technology delivers low latency when traditional SAN-attached DS8000® storage systems are used with its complementary short-distance link technology.

Low latencies are provided for read and write operations for storage systems within the 150-meter distance requirement by using a point-to-point link from the z15 to the I/O enclosure. Low I/O latencies deliver value through improved workload-elapsed times and faster transactional response times, and contribute to lower scaling costs. The implementation of zHyperLink I/O delivers service times fast enough to enable a synchronous I/O model in high-performance IBM Z® servers.

The zHyperLink function includes read and write support for Global Mirror and Global Copy functions.

zHyperLink read support

DS8A00

Improved Bandwidth with PCIe Gen4

DS8000 10th generation is designed with PCIe Gen4 enabled infrastructure. This is a significant upgrade over the PCIe Gen3 connectivity in the DS8900F, providing double the internal bandwidth across key components below:
  • New Power Servers with PCIe Gen4 support

    • The DS8000 Power servers provide integrated PCI Gen 4 controllers for connectivity to the I/O bays. The high data transfer rates that are offered by the PCIe Gen 4 internal switches provide higher I/O performance or consolidation of the I/O demands on to fewer adapters running at higher rates.

      The new power servers also enable additional write cache for 3584 GB A05 configuration which supports 192 GB of write cache compared to 128 GB for the comparable DS8950F model.

  • New IO Bays with PCIe Gen4
    • The 3U I/O bay supports 8 PCIe adapter slots providing connectivity for 4 host adapters, 2 HPFE RAID adapters and 2 zHyperLink adapters. Eash I/O bay pair is attached to the DS8000 processor nodes by two 8x PCIe Gen4 cables. The bandwidth to an I/O bay pair is doubled compared to the Gen3 I/O bay pair in the DS8900F.
  • New zHyperLink and HPFE RAID adapters

    In addition to the new processor nodes and I/O bays, the DS8000 10th generation also provides new PCIe Gen4 HPFE RAID adapters and zHyperLink adapters. These provide improved performance compared to the prior generation adapters in the DS8900F.

Next Generation zHyperLink Adapter

The zHyperLink adapter on the DS8000 G10 is built on PCIe Gen4 technology and will support connections at up to Gen4 speeds. The latency of the new adapter is reduced for reads and writes. The throughput of a single link on the new adapter is also improved.

With the reduced latency provided by the new adapter it is also now possible to support larger read sizes. The default maximum read size supported is now 16 KB and z/OS provides the ability to increase this up to 32 KB if needed for specific workloads.

zHyperLink write support

zHyperLink write operations accelerate Db2 logging for z/OS transaction processing and improve active log throughput.

Restrictions
  • zHyperLink write operations are currently supported only for Db2.
  • Models that support zHyperLink write operations include:
    • DS8884
    • DS8886
    • DS8888
    • DS8900
    • DS8A00
  • Asynchronous replication (zGlobal Mirror (XRC) and Safeguarded Copy) is not supported for zHyperLink write operations.

zHyperLink commands

The commands that DS8000 provides for zHyperLink operations include: