Novell LINUX ENTERPRISE SERVER 11 - STORAGE ADMINISTRATION GUIDE 2-23-2010, Руководство администратора, Страница: 47 / 140

Managing Multipath I/O for Devices 47
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7.2.6 Partitioning Multipath Devices
Behavior changes for how multipathed devices are handled might affect your configuration if you
are upgrading.
Š
“SUSE Linux Enterprise Server 11” on page 47
Š
“SUSE Linux Enterprise Server 10” on page 47
Š
“SUSE Linux Enterprise Server 9” on page 47
SUSE Linux Enterprise Server 11
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.
SUSE Linux Enterprise Server 10
In SUSE Linux Enterprise Server 10, the
kpartx
software is used in the
/etc/init.d/
boot.multipath
to add symlinks to the
/dev/dm-*
line in the
multipath.conf
configuration file
for any newly created partitions without requiring a reboot. This triggers
udevd
to fill in the
/dev/
disk/by-*
symlinks. The main benefit is that you can call
kpartx
with the new parameters without
rebooting the server.
SUSE Linux Enterprise Server 9
In SUSE Linux Enterprise Server 9, it is not possible to partition multipath I/O devices themselves.
If the underlying physical device is already partitioned, the multipath I/O device reflects those
partitions and the layer provides
/dev/disk/by-id/<name>p1 ... pN
devices so you can access
the partitions through the multipath I/O layer. As a consequence, the devices need to be partitioned
prior to enabling multipath I/O. If you change the partitioning in the running system, DM-MP does
not automatically detect and reflect these changes. The device must be reinitialized, which usually
requires a reboot.
7.2.7 Supported Architectures for Multipath I/O
The multipathing drivers and tools support all seven of the supported processor architectures: IA32,
AMD64/EM64T, IPF/IA64, p-Series (32-bit/64-bit), z-Series (31-bit and 64-bit).
7.2.8 Supported Storage Arrays for Multipathing
The multipathing drivers and tools support most storage arrays. The storage array that houses the
multipathed device must support multipathing in order to use the multipathing drivers and tools.
Some storage array vendors provide their own multipathing management tools. Consult the vendor’s
hardware documentation to determine what settings are required.
Š “Storage Arrays That Are Automatically Detected for Multipathing” on page 48