Novell LINUX ENTERPRISE SERVER 11 - STORAGE ADMINISTRATION GUIDE 2-23-2010, Руководство администратора, Страница: 71 / 140

Managing Multipath I/O for Devices 71
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5 After the multipathing services are started, verify that the software RAID’s component devices
are listed in the
/dev/disk/by-id
directory. Do one of the following:
Š Devices Are Listed: The device names should now have symbolic links to their Device
Mapper Multipath device names, such as
/dev/dm-1
.
Š
Devices Are Not Listed: Force the multipath service to recognize them by flushing and
rediscovering the devices.
To do this, enter the following commands:
multipath -F
multipath -v0
The devices should now be listed in
/dev/disk/by-id
, and have symbolic links to their
Device Mapper Multipath device names. For example:
lrwxrwxrwx 1 root root 10 Jun 15 09:36 scsi-mpath1 -> ../../dm-1
6 Restart the
boot.md
service and the RAID device by entering
/etc/init.d/boot.md start
7 Check the status of the software RAID by entering
mdadm --detail /dev/mapper/mpath0
The RAID’s component devices should match their Device Mapper Multipath device names
that are listed as the symbolic links of devices in the
/dev/disk/by-id
directory.
8 Make a new
initrd
to ensure that the Device Mapper Multipath services are loaded before the
RAID services on reboot. Enter
mkinitrd -f multipath
9 Reboot the server to apply these post-install configuration settings.
10 Verify that the software RAID array comes up properly on top of the multipathed devices by
checking the RAID status. Enter
mdadm --detail /dev/mapper/mpath0
For example:
Number Major Minor RaidDevice State
0 253 0 0 active sync /dev/dm-0
1 253 1 1 active sync /dev/dm-1
2 253 2 2 active sync /dev/dm-2
7.10 Scanning for New Devices without
Rebooting
If your system has already been configured for multipathing and you later need to add more storage
to the SAN, you can use the
rescan-scsi-bus.sh
script to scan for the new devices. By default,
this script scans all HBAs with typical LUN ranges.
Syntax
rescan-scsi-bus.sh [options] [host [host ...]]
You can specify hosts on the command line (deprecated), or use the
--hosts=LIST
option
(recommended).