Using Lvm2 On Multipath Devices; Using Mdadm With Multipath Devices; Using --Noflush With Multipath Devices - Novell LINUX ENTERPRISE SERVER 11 - STORAGE ADMINISTRATION GUIDE 2-23-2010 Administration Manual

7.2.3 Using LVM2 on Multipath Devices

By default, LVM2 does not recognize multipathed devices. To make LVM2 recognize the
multipathed devices as possible physical volumes, you must modify
important to modify it so that it does not scan and use the physical paths, but only accesses the
multipath I/O storage through the multipath I/O layer. If you are using user-friendly names, make
sure to specify the path so that it cans only the device mapper names for the device (
id/dm-uuid-.*-mpath-.*
To modify
1 Open the
2 Change the
filter = [ "a|/dev/disk/by-id/.*|", "r|.*|" ]
This allows LVM2 to scan only the by-id paths and reject everything else.
If you are using user-friendly names, specify the path as follows so that only the device mapper
names are scanned after multipathing is configured:
filter = [ "a|/dev/disk/by-id/dm-uuid-.*-mpath-.*|", "r|.*|" ]
3 If you are also using LVM2 on non-multipathed devices, make the necessary adjustments to
suit your setup.
filter = [ "a|/dev/disk/by-id/.*|", "r|.*|" ]
4 Save the file.
5 Add dm-multipath to
6 Make a new
changed settings. Enter
mkinitrd -f multipath
7 Reboot the server to apply the changes.

7.2.4 Using mdadm with Multipath Devices

The
mdadm
Therefore, the
DEVICE /dev/disk/by-id/*
If you are using user-friendly names, specify the path as follows so that only the device mapper
names are scanned after multipathing is configured:
DEVICE /dev/disk/by-id/dm-uuid-.*-mpath-.*

7.2.5 Using --noflush with Multipath Devices

The option --noflush should always be used when running on multipath devices.
For example, in scripts where you perform a table reload, you use the --noflush option on resume to
ensure that any outstanding I/O is not flushed, because you need the multipath topology information.
load
resume --noflush
46 SLES 11: Storage Administration Guide
) after multipathing is configured.
for multipath use:
/etc/lvm/lvm.conf
/etc/lvm/lvm.conf
and
filter types
/etc/sysconfig/kernel:INITRD_MODULES
to ensure that the Device Mapper Multipath services are loaded with the
initrd
tool requires that the devices be accessed by the ID rather than by the device node path.
entry in
DEVICE /etc/mdadm.conf
file in a text editor.
entry in
/etc/lvm/lvm.conf
should be set as follows:
. It is
/etc/lvm/lvm.conf
/dev/disk/by-
as follows:
.