Novell LINUX ENTERPRISE SERVER 11 - STORAGE ADMINISTRATION GUIDE 2-23-2010, Administration Manual, Page: 22 / 140

22 SLES 11: Storage Administration Guide
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2.4 OCFS2 File System Is in the High Availability
Release
The OCFS2 file system is fully supported as part of the SUSE Linux Enterprise High Availability
Extension.
2.5 /dev/disk/by-name Is Deprecated
The
/dev/disk/by-name
path is deprecated in SUSE Linux Enterprise Server 11 packages.
2.6 Device Name Persistence in the /dev/disk/by-
id Directory
In SUSE Linux Enterprise Server 11, the default multipath setup relies on
udev
to overwrite the
existing symbolic links in the
/dev/disk/by-id
directory when multipathing is started. Before you
start multipathing, the link points to the SCSI device with its
scsi-xxx
name. When multipathing is
running, the symbolic link points to the device using its
dm-uuid-xxx
name. This ensures that the
symbolic links in the
/dev/disk/by-id
path persistently point to the same device regardless
whether multipath is started or not. The configuration files (such as
lvm.conf
and
md.conf
) do not
need to be modified because they automatically point to the correct device.
See the following sections for more information about how this behavior change affects other
features:
Š
Section 2.7, “Filters for Multipathed Devices,” on page 22
Š
Section 2.8, “User-Friendly Names for Multipathed Devices,” on page 23
2.7 Filters for Multipathed Devices
The deprecation of the
/dev/disk/by-name
directory (as described in Section 2.5, “/dev/disk/by-
name Is Deprecated,” on page 22 ) affects how you set up filters for multipathed devices in the
configuration files. If you used the
/dev/disk/by-name
device name path for the multipath device
filters in the
/etc/lvm/lvm.conf
file, you need to modify the file to use the
/dev/disk/by-id
path. Consider the following when setting up filters that use the
by-id
path:
Š
The
/dev/disk/by-id/scsi-*
device names are persistent and created for exactly this
purpose.
Š
Do not use the
/dev/disk/by-id/dm-*
name in the filters. These are symbolic links to the
Device-Mapper devices, and result in reporting duplicate PVs in response to a
pvscan
command. The names appear to change from
LVM-pvuuid
to
dm-uuid
and back to
LVM-
pvuuid
.
For information about setting up filters, see Section 7.2.3, “Using LVM2 on Multipath Devices,” on
page 46 .