zFS (z/OS file system)

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{{Distinguish|ZFS|OpenZFS|Oracle ZFS}}

{{Infobox Filesystem

| full_name = z/OS File System

| name = zFS

| developer = IBM

| introduction_os = DCE DFS Local File System for MVS/ESA V5R2.2

| introduction_date = 1995

| partition_id =

| directory_struct =

| file_struct =

| bad_blocks_struct =

| max_filename_size =

| max_files_no =

| max_volume_size =

| max_file_size =

| filename_character_set =

| dates_recorded =

| date_range =

| date_resolution =

| forks_streams =

| attributes =

| file_system_permissions =

| compression =

| single_instance_storage =

| encryption =

| OS = z/OS (all releases), OS/390 (all releases), MVS/ESA V5R2.2

}}

z/OS File System (zFS) (official name: z/OS® Distributed File Service zSeries® File System) is a POSIX-style hierarchical file system for IBM's z/OS operating system for z System mainframes, a successor to that operating system's HFS.{{cite web

|url = http://www.ti-leipzig.de/os390/book/openmvs/hfs.pdf

|archive-url = https://web.archive.org/web/20040906071912/http://www.ti-leipzig.de/os390/book/openmvs/hfs.pdf

|archive-date = 2004-09-06

|title = Hierarchical File System

|access-date = 2016-05-12

}}

zFS technology was first released in 1995 as the Local File System, a lower layer of the DCE Distributed File System. It was available on MVS/ESA V5R2.2 and all OS/390 releases. DFS/LFS was provided as a part of the DCE feature, not part of the base operating system.

As a separate feature (outside the DCE feature), zFS was initially released for z/OS as PTFs (patches) for z/OS 1.2, with backports available for z/OS 1.1 and OS/390 2.10. Beginning with z/OS 1.3, zFS is included as a standard feature and is being actively developed.