Current limitations

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Known limitations exist for the DS8000 storage system.

The following list describes known limitations for the storage system:

  • I/O enclosure shutdown caused by low temperatures

    Bundle 88.1.17.0 or higher fixes a problem where an I/O enclosure might shutdown at temperatures below 14 C (57.2 F). The I/O enclosure firmware is not updated during a normal code load process. A pseudo exchange of the I/O enclosure updates the I/O enclosure firmware; this must be performed on each I/O enclosure separately. The process can take up to 1.5 hours per I/O enclosure and should only be considered if your environment is running at or below the listed temperature.

    Contact your IBM Service Representative during the code load process to determine whether I/O enclosure firmware should be loaded.

  • For the Dynamic Volume Expansion function, volumes cannot be in Copy Services relationships (point-in-time copy, FlashCopy® SE, Metro Mirror, Global Mirror, Metro/Global Mirror, and z/OS® Global Mirror) during expansion.
  • The size limit for single volumes in a Copy Services relationship is 2 TB. This limit does not apply to extents (when part of multiple volumes).
  • The amount of physical capacity within a 242x system that can be logically configured for use is enforced by the 242x Licensed Machine Code to maintain compliance with the extent of IBM® authorization that is established for licensed functions that are activated on the machine.
  • The deactivation of an activated licensed function, or a lateral change or reduction in the license scope, is a nondisruptive activity that occurs at the next machine IML. For example:
    • A lateral change is defined as changing the license scope from FB to CKD or from CKD to FB.
    • A reduction is defined as changing the license scope from ALL to FB or from ALL to CKD.
  • The following activities are disruptive:
    • Addition of the Earthquake Resistance Kit feature 1906.
    • Removal of an expansion model from the base model. Data is not preserved during this activity.
  • Some storage system functions are unavailable or are not supported in all environments. Go to the IBM System Storage® Interoperation Center (SSIC) website for the most current information on supported hosts, operating systems, adapters, and switches.
  • Plant configured systems with Encryption Drive Set support (feature number 1750) can support a field installation of encrypted drives. Encryption drive set deactivation support must be ordered by using feature number 1754.
  • Flash drive sets are not supported in RAID-6 or RAID-10 configurations.
  • Nearline SAS drives are not supported on RAID-5 and RAID-10 configurations.
  • Conversions between warranty machine types are not supported.
  • Thin provisioning functions are not supported on IBM Z volumes.