DFS/SMB: Prepare for the removal of DFS/SMB


z/OS V2R3 is planned to be the last release of the operating system to support Distributed File System / Server Message Block (DFS/SMB). If you need to share files between z/OS and Microsoft Windows, IBM recommends that you use the Network File System (NFS) protocol instead of DFS/SMB. Note that NFS also allows for the sharing of z/OS data with UNIX and Linux systems.

NFS is the strategic file sharing protocol for the z/OS platform. To help your installation migrate to NFS, IBM plans to deliver new NFS function on existing levels of the operating system, including installation, security, availability, and operational enhancements. These planned enhancements are intended to help you more easily migrate to NFS before you upgrade to the next release of z/OS.

Table 1 provides more details about the migration action. Use this information to plan your changes to the system.

Table 1. Information about this migration action. This table provides more details about the migration action. Use this information to plan your changes to the system.
Element or feature: Server Message Block (SMB) support of the IBM z/OS Distributed File Service base element.
When change was introduced: See IBM United States Software Announcement 218-236 "IBM z/OS Version 2 Release 3 enhancements," dated May 15, 2018.
Applies to migration from: z/OS V2R2 and z/OS V2R1.
Timing: Before installing z/OS V2R3.
Is the migration action required? No, but recommended because DFS/SMB is planned to be removed in the release after z/OS V2R3.
Target system hardware requirements: None.
Target system software requirements: None.
Other system (coexistence or fallback) requirements: None.
Restrictions: None.
System impacts: None.
Related IBM® Health Checker for z/OS® check: You can use health check ZOSMIGV2R3_NEXT_USS_SMB_DETECTED to determine whether your system uses DFS/SMB. This check, which is added by APAR OA56251, is available for z/OS V2R2 and z/OS V2R3 systems.

Steps to take

Do the following:
  1. Determine whether your system uses DFS/SMB. To do so, use health check ZOSMIGV2R3_NEXT_USS_SMB_DETECTED.
  2. If so, stop using DFS/SMB. Instead, use equivalent functions in NFS.

Reference information

For more information, see z/OS Network File System Guide and Reference.