VFS_GPFS(8) System Administration tools VFS_GPFS(8)NAMEvfs_gpfs - gpfs specific samba extensions like acls and prealloc
SYNOPSIS
vfs objects = gpfs
DESCRIPTION
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 :
· NFSv4 ACL Interfaces with configurable options for GPFS
· Kernel oplock support on GPFS
· 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 is stackable.
OPTIONS
gpfs:sharemodes = [ yes | no ]
Enable/Disable cross node sharemode handling for GPFS.
· yes(default) - propagate sharemodes across all GPFS nodes.
· 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 files.
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.
· yes(default) - propagate leases across all GPFS nodes.
· 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 files.
gpfs:hsm = [ yes | no ]
Enable/Disable announcing if this FS has HSM enabled.
· no(default) - Do not announce HSM.
· no - Announce HSM.
gpfs:getrealfilename = [ yes | no ]
Enable/Disable usage of the gpfs_get_realfilename_path() function.
This improves the casesensitive wildcard file name access.
· yes(default) - use gpfs_get_realfilename_path().
· 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.
· no(default) - do not use GPFS windows attributes.
· yes - use GPFS windows attributes.
gpfs:merge_writeappend = [ yes | no ]
GPFS ACLs doesn´t know about the ´APPEND´ right. This optionen lets
Samba map the ´APPEND´ right to ´WRITE´.
· yes(default) - map ´APPEND´ to ´WRITE´.
· no - do not map ´APPEND´ to ´WRITE´.
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
· no(default) - ignore the DESC_DACL_PROTECTED flags.
· yes - reject ACLs with DESC_DACL_PROTECTED.
nfs4:mode = [ simple | special ]
Enable/Disable substitution of special IDs on GPFS. This parameter
should not affect the windows users in anyway. It only ensures that
Samba sets the special IDs - OWNER@ and GROUP@ ( mappings to simple
uids ) that are relevant to GPFS.
The following MODEs are understood by the module:
· simple(default) - do not use special IDs in GPFS ACEs
· special - use special IDs in GPFS 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 :
· dontcare (default) - copy the ACEs as they come
· reject - stop operation and exit with error on ACL set op
· ignore - don´t include the second matching ACE
· 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 :
· yes - Enable chown if as supported by the under filesystem
· 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
files.
Following is the behaviour of Samba for different values:
· yesOpen files with O_SYNC
· no (default)Open files as normal Samba would do
EXAMPLES
A GPFS mount can be exported via Samba as follows :
[samba_gpfs_share]
vfs objects = gpfs
path = /test/gpfs_mount
nfs4: mode = special
nfs4: acedup = merge
CAVEATS
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
time.
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.
VERSION
This man page is correct for version 3.0.25 of the Samba suite.
AUTHOR
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
Samba 3.6 01/22/2012 VFS_GPFS(8)
