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man pages section 8: System Administration Commands

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Updated: Thursday, June 13, 2019

vfs_gpfs (8)


vfs_gpfs - gpfs specific samba extensions like acls and prealloc


vfs objects = gpfs


System Administration tools                                        VFS_GPFS(8)

       vfs_gpfs - gpfs specific samba extensions like acls and prealloc

       vfs objects = gpfs

       This VFS module is part of the samba(7) suite.

       The gpfs VFS module is the home for all gpfs extensions that Samba
       requires for proper integration with GPFS. It uses the GPL library
       interfaces provided by GPFS.

       Currently the gpfs vfs module provides extensions in following areas :

              o   NFSv4 ACL Interfaces with configurable options for GPFS

              o   Kernel oplock support on GPFS

              o   Lease support on GPFS

       NOTE: This module follows the posix-acl behaviour and hence allows
       permission stealing via chown. Samba might allow at a later point in
       time, to restrict the chown via this module as such restrictions are
       the responsibility of the underlying filesystem than of Samba.

       This module makes use of the smb.conf parameter acl map full control.
       When set to yes (the default), this parameter will add in the
       FILE_DELETE_CHILD bit on a returned ACE entry for a file (not a
       directory) that already contains all file permissions except for
       FILE_DELETE and FILE_DELETE_CHILD. This can prevent Windows
       applications that request GENERIC_ALL access from getting ACCESS_DENIED
       errors when running against a filesystem with NFSv4 compatible ACLs.

       This module is stackable.

       Since Samba 4.0 all options are per share options.

       gpfs:sharemodes = [ yes | no ]
           Enable/Disable cross node sharemode handling for GPFS.

                  o    yes(default) - propagate sharemodes across all GPFS

                  o    no - do not propagate sharemodes across all GPFS nodes.
                      This should only be used if the GPFS file system is
                      exclusively exported by Samba. Access by local unix
                      application or NFS exports could lead to corrupted

       gpfs:leases = [ yes | no ]
           Enable/Disable cross node leases (oplocks) for GPFS. You should
           also set the oplocks and kernel oplocks options to the same value.

                  o    yes(default) - propagate leases across all GPFS nodes.

                  o    no - do not propagate leases across all GPFS nodes.
                      This should only be used if the GPFS file system is
                      exclusively exported by Samba. Access by local unix
                      application or NFS exports could lead to corrupted

       gpfs:hsm = [ yes | no ]
           Enable/Disable announcing if this FS has HSM enabled.

                  o    no(default) - Do not announce HSM.

                  o    yes - Announce HSM.

       gpfs:recalls = [ yes | no ]
           When this option is set to no, an attempt to open an offline file
           will be rejected with access denied. This helps preventing recall
           storms triggered by careless applications like Finder and Explorer.

                  o   yes(default) - Open files that are offline. This will
                      recall the files from HSM.

                  o   no - Reject access to offline files with access denied.
                      This will prevent recalls of files from HSM. Using this
                      setting also requires gpfs:hsm to be set to yes.

       gpfs:getrealfilename = [ yes | no ]
           Enable/Disable usage of the gpfs_get_realfilename_path() function.
           This improves the casesensitive wildcard file name access.

                  o    yes(default) - use gpfs_get_realfilename_path().

                  o    no - do not use gpfs_get_realfilename_path(). It seems
                      that gpfs_get_realfilename_path() doesn't work on AIX.

       gpfs:winattr = [ yes | no ]
           Enable/Disable usage of the windows attributes in GPFS. GPFS is
           able to store windows file attributes e.g. HIDDEN, READONLY, SYSTEM
           and others natively. That means Samba doesn't need to map them to
           permission bits or extended attributes.

                  o    no(default) - do not use GPFS windows attributes.

                  o    yes - use GPFS windows attributes.

       gpfs:merge_writeappend = [ yes | no ]
           GPFS ACLs doesn't know about the 'APPEND' right. This option lets
           Samba map the 'APPEND' right to 'WRITE'.

                  o    yes(default) - map 'APPEND' to 'WRITE'.

                  o    no - do not map 'APPEND' to 'WRITE'.

       gpfs:acl = [ yes | no ]
           This option lets Samba use or ignore GPFS ACLs.

                  o    yes(default) - use GPFS ACLs.

                  o    no - do not use GPFS ACLs and pass everything to the
                      next SMB_VFS module.

       gpfs:refuse_dacl_protected = [ yes | no ]
           As GPFS does not support the ACE4_FLAG_NO_PROPAGATE NFSv4 flag
           (which would be the mapping for the DESC_DACL_PROTECTED flag), the
           status of this flag is currently silently ignored by Samba. That
           means that if you deselect the "Allow inheritable permissions..."
           checkbox in Windows' ACL dialog and then apply the ACL, the flag
           will be back immediately.

           To make sure that automatic migration with e.g. robocopy does not
           lead to ACLs silently (and unintentionally) changed, you can set
           gpfs:refuse_dacl_protected = yes to enable an explicit check for
           this flag and if set, it will return NT_STATUS_NOT_SUPPORTED so
           errors are shown up on the Windows side and the Administrator is
           aware of the ACLs not being settable like intended

                  o    no(default) - ignore the DESC_DACL_PROTECTED flags.

                  o    yes - reject ACLs with DESC_DACL_PROTECTED.

       gpfs:dfreequota = [ yes | no ]
           Adjust reporting of the size and free space of a share according to
           quotas. If this setting is "yes", a request for size and free space
           will also evaluate the user quota of the user requesting the data
           and the group quota of the primary group of the user. Fileset
           quotas are not queried, since GPFS already provides the option
           --dfreequota to reflect the fileset quota in the free space query.
           Please use that option to include fileset quotas in the reported
           disk space.

           If any of the soft or hard quota limits has been reached, the free
           space will be reported as 0. If a quota is in place, but the limits
           have not been reached, the free space will be reported according to
           the space left in the quota. If more than one quota applies the
           free space will be reported as the smallest space left in those
           quotas. The size of the share will be reported according to the
           quota usage. If more than one quota applies, the smallest size will
           be reported for the share size according to these quotas.

                  o    yes - include the quotas when reporting the share size
                      and free space

                  o    no(default) - do not include quotas, simply report the
                      size and free space of the file system

       gpfs:prealloc = [ yes | no ]
           If set to yes the gpfs_prealloc function will be used in the
           fallocate callback when appropriate. If set to no gpfs_prealloc
           will not be used. In both cases the system and libc calls are

                  o    yes (default) - Use gpfs_prealloc for the fallocate

                  o    no - Do not use gpfs_prealloc for the fallocate

       gpfs:settimes = [ yes | no ]
           Use the gpfs_set_times API when changing the timestamps of a file
           or directory. If the GPFS API is not available the old method of
           using utime and the GPFS winattr call will be used instead.

                  o    yes(default) - Use gpfs_set_times. Fall back to utime
                      and winattr when it is not available.

                  o    no - Do not use gpfs_set_times.

       nfs4:mode = [ simple | special ]
           Controls substitution of special IDs (OWNER@ and GROUP@) on GPFS.
           The use of mode simple is recommended. In this mode only non
           inheriting ACL entries for the file owner and group are mapped to
           special IDs.

           The following MODEs are understood by the module:

                  o   simple(default) - use OWNER@ and GROUP@ special IDs for
                      non inheriting ACEs only.

                  o   special(deprecated) - use OWNER@ and GROUP@ special IDs
                      in ACEs for all file owner and group ACEs.

       nfs4:acedup = [dontcare|reject|ignore|merge]
           This parameter configures how Samba handles duplicate ACEs
           encountered in GPFS ACLs. GPFS allows/creates duplicate ACE for
           different bits for same ID.

           Following is the behaviour of Samba for different values :

                  o   dontcare (default) - copy the ACEs as they come

                  o   reject - stop operation and exit with error on ACL set

                  o   ignore - don't include the second matching ACE

                  o   merge - bitwise OR the 2 ace.flag fields and 2 ace.mask
                      fields of the 2 duplicate ACEs into 1 ACE

       nfs4:chown = [yes|no]
           This parameter allows enabling or disabling the chown supported by
           the underlying filesystem. This parameter should be enabled with
           care as it might leave your system insecure.

           Some filesystems allow chown as a) giving b) stealing. It is the
           latter that is considered a risk.

           Following is the behaviour of Samba for different values :

                  o   yes - Enable chown if as supported by the under

                  o   no (default) - Disable chown

       gpfs:syncio = [yes|no]
           This parameter makes Samba open all files with O_SYNC. This
           triggers optimizations in GPFS for workloads that heavily share

           Following is the behaviour of Samba for different values:

                  o   yes - Open files with O_SYNC

                  o   no (default) - Open files as normal Samba would do

       A GPFS mount can be exported via Samba as follows :

                vfs objects = gpfs
                path = /test/gpfs_mount
                nfs4: mode = special
                nfs4: acedup = merge

       Depending on the version of gpfs, the libgpfs_gpl library or the
       libgpfs library is needed at runtime by the gpfs VFS module: Starting
       with gpfs 3.2.1 PTF8, the complete libgpfs is available as open source
       and libgpfs_gpl does no longer exist. With earlier versions of gpfs,
       only the libgpfs_gpl library was open source and could be used at run

       At build time, only the header file gpfs_gpl.h is required, which is a
       symlink to gpfs.h in gpfs versions newer than 3.2.1 PTF8.

       This man page is part of version 4.9.3 of the Samba suite.

       The original Samba software and related utilities were created by
       Andrew Tridgell. Samba is now developed by the Samba Team as an Open
       Source project similar to the way the Linux kernel is developed.

       The GPFS VFS module was created with contributions from Volker Lendecke
       and the developers at IBM.

       This manpage was created by the IBM FSCC team

       See attributes(7) for descriptions of the following attributes:

       |Availability   | service/network/samba |
       |Stability      | Volatile              |
       This software was built from source available at
       https://github.com/oracle/solaris-userland.  The original community
       source was downloaded from

       Further information about this software can be found on the open source
       community website at http://www.samba.org/.

Samba 4.9.3                       01/24/2019                       VFS_GPFS(8)