Device blacklisting
Devices can be blacklisted for multipath-tools. The default configuration blacklists some well-known local devices, such as
/dev/cciss. Depending on the SCSI controller, others might be needed.
To determine the drives that need to be blacklisted from multipath-tools, issue:
fdisk -l
Some Fujitsu-Siemens (and other) machines use the LSI MegaRAID which makes the local device available as
/dev/sda. For those, a blacklist-entry for
/dev/sda should be added to
.
Some HP (and other) machines use the cciss driver. Make sure that /dev/sdais not blacklisted in /etc/multipath.config or a device will be missing.
Unique device IDs
Multipath determines unique device IDs using the scsi_id command. Some controllers do not support the device-queries used by scsi_id to determine device IDs.
The error logged to syslog when the Kernel modules are loaded:
/etc/init.d/boot.multipath
/etc/hotplug/scsi_generic.agent[pid]: 2:0:0:0: neither page 0x83 nor 0x80 supported
# unsuccessful queriyng of SCSI page 0x80
scsi_id -g -v -p 0x80 -s /block/sda
set_options: option 'p' arg '0x80'
set_options: option 's' arg '/block/sda'
scsi_id: target_path /sys/block/sda
get_blockdev_parent: sda not a partition
scsi_id: class_dev 0x0x40000010; class_dev_parent 0x0x00000000
sysfs_path_is_link: stat() failed
sysfs_path_is_link: stat() failed
sysfs_path_is_link: stat() failed
sysfs_path_is_link: stat() failed
create_tmp_dev: (/sys/block/sda)
sysfs_get_attr: /sys/block/sda/dev
get_major_minor: dev value 8:0
create_tmp_dev: tmpdev '/tmp/scsi-maj8-min0-26015'
sysfs_get_attr: /sys/devices/pci0000:01/0000:01:0c.0/host0/0:0:0:0/vendor
sysfs_get_attr: /sys/devices/pci0000:01/0000:01:0c.0/host0/0:0:0:0/model
get_file_options: vendor='MegaRAID
'; model='LD0 RAID1 34700R
'
get_file_options: config file line 33: vendor 'someone'; model 'nicedrive'; options '-g'
get_file_options: no match
get_file_options: config file line 44: vendor 'MegaRAID'; model 'LD0 RAID1 34700R'; options '-b'
get_file_options: matched vendor/model
per_dev_options: option 'b' arg '/block/sda'
scsi_id: per dev options: good 0; page code 0x80; callout ''
scsi_id: buffer unaligned 0x0x40001550; aligned 0x0x40001600
Hitachi OPEN-V, page 0x80
scsi_id -g -v -p 0x80 -s /block/sdi
set_options: option 'p' arg '0x80'
set_options: option 's' arg '/block/sdi'
scsi_id: target_path /sys/block/sdi
get_blockdev_parent: sdi not a partition
scsi_id: class_dev 0x0x0000002a95556020; class_dev_parent 0x0x0000000000000000
sysfs_path_is_link: stat() failed
sysfs_path_is_link: stat() failed
sysfs_path_is_link: stat() failed
create_tmp_dev: (/sys/block/sdi)
sysfs_get_attr: /sys/block/sdi/dev
get_major_minor: dev value 8:128
create_tmp_dev: tmpdev '/tmp/scsi-maj8-min128-16598'
sysfs_get_attr: /sys/devices/pci0000:04/0000:04:0a.0/0000:07:09.0/host1/1:0:1:0/vendor
sysfs_get_attr: /sys/devices/pci0000:04/0000:04:0a.0/0000:07:09.0/host1/1:0:1:0/model
get_file_options: vendor='HITACHI
'; model='OPEN-V
'
get_file_options: can't open /etc/scsi_id.config
scsi_id: per dev options: good 1; page code 0x80; callout ''
scsi_id: buffer unaligned 0x0x0000002a95557700; aligned 0x0x0000002a95557800
scsi_get_serial: opening /tmp/scsi-maj8-min128-16598
scsi_inquiry: 1:0:1:0 evpd 1, page 0x0
scsi_inquiry: 1:0:1:0 evpd 1, page 0x80
sysfs_get_attr: /sys/devices/pci0000:04/0000:04:0a.0/0000:07:09.0/host1/1:0:1:0/vendor
sysfs_get_attr: /sys/devices/pci0000:04/0000:04:0a.0/0000:07:09.0/host1/1:0:1:0/model
SHITACHI OPEN-V 10976
scsi_id: SHITACHI OPEN-V 10976
Hitachi OPEN-V, page 0x83
scsi_id -g -v -p 0x83 -s /block/sdi
set_options: option 'p' arg '0x83'
set_options: option 's' arg '/block/sdi'
scsi_id: target_path /sys/block/sdi
get_blockdev_parent: sdi not a partition
scsi_id: class_dev 0x0x0000002a95556020; class_dev_parent 0x0x0000000000000000
sysfs_path_is_link: stat() failed
sysfs_path_is_link: stat() failed
sysfs_path_is_link: stat() failed
create_tmp_dev: (/sys/block/sdi)
sysfs_get_attr: /sys/block/sdi/dev
get_major_minor: dev value 8:128
create_tmp_dev: tmpdev '/tmp/scsi-maj8-min128-16597'
sysfs_get_attr: /sys/devices/pci0000:04/0000:04:0a.0/0000:07:09.0/host1/1:0:1:0/vendor
sysfs_get_attr: /sys/devices/pci0000:04/0000:04:0a.0/0000:07:09.0/host1/1:0:1:0/model
get_file_options: vendor='HITACHI
'; model='OPEN-V
'
get_file_options: can't open /etc/scsi_id.config
scsi_id: per dev options: good 1; page code 0x83; callout ''
scsi_id: buffer unaligned 0x0x0000002a95557700; aligned 0x0x0000002a95557800
scsi_get_serial: opening /tmp/scsi-maj8-min128-16597
scsi_inquiry: 1:0:1:0 evpd 1, page 0x0
scsi_inquiry: 1:0:1:0 evpd 1, page 0x83
do_scsi_page83_inquiry: 1:0:1:0 id desc 3/6/1
do_scsi_page83_inquiry: not used
do_scsi_page83_inquiry: 1:0:1:0 id desc 3/6/1
do_scsi_page83_inquiry: not used
do_scsi_page83_inquiry: 1:0:1:0 id desc 3/6/1
do_scsi_page83_inquiry: used
360060e80042ae00000002ae000000442
scsi_id: 360060e80042ae00000002ae000000442
Devices queried by scsi_id can be filtered-out by setting some options in /etc/scsi_id.config
# comment-out "setting all drives as good"
## options=-g
# add filter for controller (parameters obtained by scsi_id)
vendor=MegaRAID, model="LD0 RAID1 34700R", options=-b
Loading the Kernel modules
/etc/init.d/boot.multipath will load the multipath modules and create the disks under /dev/disk.
Check if the LUNs from the SAN have been found. This should show you the devices with their WWID.
# ls -al /dev/disk/by-name/
total 8
drwxr-xr-x 2 root root 4096 Dec 21 10:07 .
drwxr-xr-x 5 root root 4096 Dec 21 10:07 ..
lrwxrwxrwx 1 root root 10 Dec 21 10:07 1HITACHI_D60H58500424 -> ../../dm-4
lrwxrwxrwx 1 root root 10 Dec 21 10:07 1HITACHI_D60H58500424p1 -> ../../dm-9
lrwxrwxrwx 1 root root 10 Dec 21 10:07 1HITACHI_D60H58500434 -> ../../dm-0
lrwxrwxrwx 1 root root 10 Dec 21 10:07 1HITACHI_D60H58500434p1 -> ../../dm-7
lrwxrwxrwx 1 root root 10 Dec 21 10:07 1HITACHI_D60H58500479 -> ../../dm-1
lrwxrwxrwx 1 root root 10 Dec 21 10:07 1HITACHI_D60H58500479p1 -> ../../dm-6
lrwxrwxrwx 1 root root 10 Dec 21 10:07 360060e80042ae00000002ae000000442 -> ../../dm-2
lrwxrwxrwx 1 root root 10 Dec 21 10:07 360060e80042ae00000002ae000000442p1 -> ../../dm-8
lrwxrwxrwx 1 root root 10 Dec 21 10:07 360060e80042ae00000002ae000000443 -> ../../dm-3
lrwxrwxrwx 1 root root 10 Dec 21 10:07 360060e80042ae00000002ae000000443p1 -> ../../dm-5
Note: The first 3 devices are from a Hitachi DF600F, the other two from a Hitachi 9500.
If you want multipath to name your devices you can create {multipath}-entries in /etc/multipath.conf.
You would use either the WWID or the alias created in /etc/multipath.conf to mount the devices.
Persistent device naming is currently discussed on the mailinglist.