IBM z/OS 3.1 was announced on August 8th, 2023 and made generally available September 29th, 2023. z/OS 3.1 intends to follow the traditional z/OS continuous delivery (CD) model by delivering new features and enhanced capabilities quarterly, which is intended to avoid the effort of a full release upgrade with no impact to stability, complexity or costs. The following enhancements have been delivered for z/OS 3.1 in 1Q 2025.
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Editors note: Previously included in this blog was information on ‘zCX Sysplex Distributor for OCP’ via APAR OA66817. This item has since been removed, for the time being.
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Overview:
As previously announced, clients are encouraged to migrate to the latest level of Java:
- Semeru 21 Migration. Semeru 17 will go end of market (EOM) on October 6th, 2025 and end of service (EOS) on September 30, 2026. Clients are encouraged to move to Semeru 21 prior to the EOM date for a seamless transition.
With the following enhancements, z/OS infrastructure architects can benefit from workload distribution functions and problem-prevention health checks to support the high availability of their systems:
- z/OS UNIX File System Health Checker. A new health check helps to aid customers in the configuration of their z/OS UNIX file system and drive consistency of file system configuration according to best practices, while still allowing flexibility for individual customer-unique scenarios.
- Multiple VIPA ranges for z/OS Container Platform. This enhancement enables the configuration and use of multiple VIPARANGE ZCONTAINER statements for use by containers started with z/OS Container Platform (zOSCP).
z/OS infrastructure architects and storage administrators can utilize the following enhancements, designed to better manage the growth of data and eliminate impactful data constraints and complexities:
- DFSMS cloud object storage enhancements. z/OS applications utilizing Cloud Data Access (CDA) can specify compression for object data. By leveraging CDA, DFSMSdss (DSS) provides the ability to dump and restore backups directly to and from cloud object storage.
z/OS security architects can ensure they’re meeting regulatory and compliance requirements with the following enhancement:
- SMTP AUTH support for CSSMTP. Support has been added for the SMTP AUTH command to satisfy regulatory compliance and ensure interoperability with email servers requesting client authentication.
- RACF LDAPBIND password protection updates. RACF’s LDAPBIND now provides the option of quantum-safe encryption for its operations.
- DFSMS Optimization Mode for Data Set Copy. Enhancements provide the ability to move data within the access methods without decrypting/uncompressing.
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Description:
Migration from IBM Semeru 17 to Semeru 21
As documented, Semeru 17 will go end of market (EOM) on October 6th, 2025, and end of service (EOS) on September 30, 2026. Semeru 17 will no longer be available for download on Shopz following the EOM date. As per announcement AD24-0783, clients are instead encouraged to move to Semeru 21 prior to October 6th for a seamless transition. Please see the z/OS 3.1 Planning for Installation guide for additional details.
z/OS UNIX File System Health Checker
A new health check is being provided to aid customers in the configuration of their z/OS UNIX file system, for both single system and shared file system (sysplex) environments. This health check will help drive consistency of file system configuration according to best practices, while still allowing flexibility for individual customer-unique scenarios. With the PTF for APAR OA67191, this enhancement is available on z/OS V2.5 and above.
Multiple VIPA ranges for z/OS Container Platform
z/OS Communications Server is enhanced to enable the configuration and use of multiple VIPARANGE ZCONTAINER statements for use by containers started with z/OS Container Platform (zOSCP). Previously, the TCP/IP stack could dynamically request Dynamic Virtual IP Addresses (DVIPAs) from a single configured range of addresses per stack. This new feature expands this functionality to allow users to configure more than one of these ranges for address creation in the TCP/IP profile. This alleviates the restriction where customers would need to ensure they had enough available contiguous addresses. With the PTF for APAR PH63940, this enhancement is available z/OS 2.5 and above.
DFSMS cloud object storage enhancements
IBM z/OS clients are integrating cloud object storage into their classic disk and tape environments to create a hybrid storage architecture. This hybrid architecture enables clients to leverage the strengths of on-premise disk and tape storage while adding the intrinsic strengths of cloud solutions for backup, archive, and unstructured data to enable new use cases and increase business agility, while reducing the complexity of their storage environments. With z/OS 3.1, a new callable service, Cloud Data Access (CDA), was introduced with a common set of APIs to enable direct access to data in cloud object stores, allowing object data to be incorporated into z/OS workloads and unlocking new levels of flexibility and efficiency in data management.
DFSMSdfp CDA is enhanced to be able to compress data before storing it in cloud object storage and to automatically decompress the data after retrieving it. CDA provides a new compression parameter for the GDKWRITE APIs to request either zEnterprise Data Compression (zEDC) or gzip compression be used. Additionally, the GDKUTIL utility is updated with a new compression keyword for the UPLOAD commands to specify either zEDC or gzip compression. With the PTF for APAR OA66536, this support is available on z/OS 3.1.
DFSMSdss (DSS) DUMP and RESTORE commands are enhanced to use CDA APIs to store and retrieve objects directly from cloud object storage, which includes all cloud storage providers supported by CDA. DSS will utilize the new CDA compression support, and zEnterprise Data Compression (zEDC) can be specified for these new cloud object storage backups. Usage will require a CDA cloud provider file with appropriate configuration details for each cloud intended to be used for DSS backup and restore. In addition to existing DS8000 Transparent Cloud Tiering (TCT), this new, software only direct-to-cloud solution provides another option to incorporate cloud object storage into z/OS environments, providing users with more flexibility, more choices, and more ways to simplify their storage strategy. With the PTFs for APARs OA66450 and OA67394, this support is available on z/OS 3.1.
SMTP AUTH support for CSSMTP
CSSMTP, the z/OS email client, is enhanced to support the SMTP AUTH command in a manner that is consistent with RFC 4954. This provides a mechanism to allow mail servers to authenticate the originator of email. This is intended to satisfy regulatory compliance and ensure interoperability with email servers requesting client authentication. With the PTF for APAR PH61015, this enhancement will be available on z/OS V2.5 and above.
RACF LDAPBIND password protection updates
RACF provides functions for encrypting and decrypting passwords for external servers such as LDAP via the KEYSMSTR class. New enhancements in the RACF KEYSMSTR class functions will provide an option for quantum-safe encryption with support for the AES encryption algorithm. With the PTF for APAR OA66458, this enhancement will be available on z/OS V2.5 and above.
DFSMS Optimization Mode for Data Set Copy
Continued enhancements to pervasive encryption delivers a new interface for VSAM encrypted data sets and sequential encrypted extended format data sets that provides the capability to optimize copying from a source to target encrypted data set, with similar characteristics, where both have the same key label, while making the copy operation more secure since the data remains encrypted throughout the copy. There is an intended performance benefit to not having to decrypt the data on input and then re-encrypting the data on output.
This enhancement also provides the capability to optimize copying sequential extended format compressed data sets with similar characteristics using BSAM so that the data does not have to be decompressed and recompressed. There is also an intended performance benefit to not having to decompress the data on input and then recompress it on output. Similar support for VSAM is already available.
Initial exploitation of this new capability will be provided with IDCAMS REPRO. With the associated PTFs for APAR OA63434, this enhancement is available on z/OS V2.5 and above.
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In addition to the above z/OS enhancements, learn more about recent AI Enhancements and Updates for the z/OS Ecosystem here.
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