0

I tried to install multipathing on a Centos 7.5 host following some links like

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/dm_multipath/mpio_components

https://www.learnitguide.net/2016/06/how-to-configure-multipathing-in-linux.html

I fear I missed something as the output of "ssm list" states:

ssm list
--------------------------------------------------------------
Device          Free      Used      Total  Pool    Mount point
--------------------------------------------------------------
/dev/sda                        222.59 GB          PARTITIONED
/dev/sda1                         1.00 GB          /boot
/dev/sda2  167.58 GB  54.00 GB  221.58 GB  centos
/dev/sdb                        200.00 GB
/dev/sdc                        200.00 GB
/dev/sdd                          1.00 TB
/dev/sde                          1.00 TB
/dev/sdf                          1.17 TB
/dev/sdg                          1.17 TB
/dev/sdh                        200.00 GB
/dev/sdi                        200.00 GB
/dev/sdj                          1.00 TB
/dev/sdk                          1.00 TB
/dev/sdl                          1.17 TB
/dev/sdm                          1.17 TB
/dev/sdn                        200.00 GB
/dev/sdo                        200.00 GB
/dev/sdp                          1.00 TB
/dev/sdq                          1.00 TB
/dev/sdr                          1.17 TB
/dev/sds                          1.17 TB
/dev/sdt                        200.00 GB
/dev/sdu                        200.00 GB
/dev/sdv                          1.00 TB
/dev/sdw                          1.00 TB
/dev/sdx                          1.17 TB
/dev/sdy                          1.17 TB
--------------------------------------------------------------
-----------------------------------------------------
Pool    Type  Devices       Free      Used      Total
-----------------------------------------------------
centos  lvm   1        167.58 GB  54.00 GB  221.58 GB
-----------------------------------------------------
--------------------------------------------------------------------------------------
Volume            Pool    Volume size  FS      FS size       Free  Type    Mount point
--------------------------------------------------------------------------------------
/dev/centos/root  centos     50.00 GB  xfs    49.98 GB   47.89 GB  linear  /
/dev/centos/swap  centos      4.00 GB                              linear
/dev/sda1                     1.00 GB  xfs  1014.00 MB  732.00 MB  part    /boot
--------------------------------------------------------------------------------------

Thought when installing dm-multipath the os hides the multiple /dev/sd* devices?

several outputs:

multipath -l:

3600a098038303561325d474f4b597539 dm-3 NETAPP  ,LUN C-Mode
size=1.0T features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=0 status=active
| |- 1:0:1:1 sdk 8:160  active undef unknown
| |- 1:0:3:1 sdw 65:96  active undef unknown
| |- 8:0:1:1 sdj 8:144  active undef unknown
| `- 8:0:2:1 sdp 8:240  active undef unknown
`-+- policy='service-time 0' prio=0 status=enabled
  |- 1:0:0:1 sde 8:64   active undef unknown
  |- 1:0:2:1 sdq 65:0   active undef unknown
  |- 8:0:0:1 sdd 8:48   active undef unknown
  `- 8:0:3:1 sdv 65:80  active undef unknown
san_disk1 (3600a098038303561325d474f4b59752d) dm-4 NETAPP  ,LUN C-Mode
size=1.2T features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=0 status=active
| |- 1:0:1:2 sdm 8:192  active undef unknown
| |- 1:0:3:2 sdx 65:112 active undef unknown
| |- 8:0:1:2 sdl 8:176  active undef unknown
| `- 8:0:2:2 sdr 65:16  active undef unknown
`-+- policy='service-time 0' prio=0 status=enabled
  |- 1:0:0:2 sdg 8:96   active undef unknown
  |- 1:0:2:2 sds 65:32  active undef unknown
  |- 8:0:0:2 sdf 8:80   active undef unknown
  `- 8:0:3:2 sdy 65:128 active undef unknown
3600a098038303561325d474f4b597538 dm-2 NETAPP  ,LUN C-Mode
size=200G features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=0 status=active
| |- 1:0:1:0 sdi 8:128  active undef unknown
| |- 1:0:3:0 sdu 65:64  active undef unknown
| |- 8:0:1:0 sdh 8:112  active undef unknown
| `- 8:0:2:0 sdn 8:208  active undef unknown
`-+- policy='service-time 0' prio=0 status=enabled
  |- 1:0:0:0 sdc 8:32   active undef unknown
  |- 1:0:2:0 sdo 8:224  active undef unknown
  |- 8:0:0:0 sdb 8:16   active undef unknown
  `- 8:0:3:0 sdt 65:48  active undef unknown

multipath -ll

3600a098038303561325d474f4b597539 dm-3 NETAPP  ,LUN C-Mode
size=1.0T features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 1:0:1:1 sdk 8:160  active ready running
| |- 1:0:3:1 sdw 65:96  active ready running
| |- 8:0:1:1 sdj 8:144  active ready running
| `- 8:0:2:1 sdp 8:240  active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  |- 1:0:0:1 sde 8:64   active ready running
  |- 1:0:2:1 sdq 65:0   active ready running
  |- 8:0:0:1 sdd 8:48   active ready running
  `- 8:0:3:1 sdv 65:80  active ready running
san_disk1 (3600a098038303561325d474f4b59752d) dm-4 NETAPP  ,LUN C-Mode
size=1.2T features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 1:0:1:2 sdm 8:192  active ready running
| |- 1:0:3:2 sdx 65:112 active ready running
| |- 8:0:1:2 sdl 8:176  active ready running
| `- 8:0:2:2 sdr 65:16  active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  |- 1:0:0:2 sdg 8:96   active ready running
  |- 1:0:2:2 sds 65:32  active ready running
  |- 8:0:0:2 sdf 8:80   active ready running
  `- 8:0:3:2 sdy 65:128 active ready running
3600a098038303561325d474f4b597538 dm-2 NETAPP  ,LUN C-Mode
size=200G features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw
|-+- policy='service-time 0' prio=50 status=active
| |- 1:0:1:0 sdi 8:128  active ready running
| |- 1:0:3:0 sdu 65:64  active ready running
| |- 8:0:1:0 sdh 8:112  active ready running
| `- 8:0:2:0 sdn 8:208  active ready running
`-+- policy='service-time 0' prio=10 status=enabled
  |- 1:0:0:0 sdc 8:32   active ready running
  |- 1:0:2:0 sdo 8:224  active ready running
  |- 8:0:0:0 sdb 8:16   active ready running
  `- 8:0:3:0 sdt 65:48  active ready running

cat /etc/multipath.conf defaults { user_friendly_names yes #path_grouping_policy multibus find_multipaths yes path_grouping_policy failover }

 blacklist {
    devnode "sda"
}

 multipaths {
    multipath {
            wwid 3600a098038303561325d474f4b59752d
            alias san_disk1
    }
}

service multipathd status

Redirecting to /bin/systemctl status multipathd.service
● multipathd.service - Device-Mapper Multipath Device Controller
   Loaded: loaded (/usr/lib/systemd/system/multipathd.service; enabled; vendor preset: enabled)
   Active: active (running) since Mon 2018-07-09 12:12:27 CEST; 2min 19s ago
  Process: 19275 ExecStart=/sbin/multipathd (code=exited, status=0/SUCCESS)
  Process: 19272 ExecStartPre=/sbin/multipath -A (code=exited, status=0/SUCCESS)
  Process: 19268 ExecStartPre=/sbin/modprobe dm-multipath (code=exited, status=0/SUCCESS)
 Main PID: 19277 (multipathd)
    Tasks: 9
   CGroup: /system.slice/multipathd.service
           └─19277 /sbin/multipathd

Jul 09 12:12:27 VIGT01-101.res01.ads.ooe.local systemd[1]: Starting Device-Mapper Multipath Device Controller...
Jul 09 12:12:27 VIGT01-101.res01.ads.ooe.local systemd[1]: Started Device-Mapper Multipath Device Controller.
Jul 09 12:12:27 VIGT01-101.res01.ads.ooe.local multipathd[19277]: 3600a098038303561325d474f4b597538: load table [0 419430400 multipath 4 queue_if_no_path pg...65:48 1]
Jul 09 12:12:27 VIGT01-101.res01.ads.ooe.local multipathd[19277]: 3600a098038303561325d474f4b597539: load table [0 2147518464 multipath 4 queue_if_no_path p...65:80 1]
Jul 09 12:12:27 VIGT01-101.res01.ads.ooe.local multipathd[19277]: san_disk1: load table [0 2516901888 multipath 4 queue_if_no_path pg_init_retries 50 retain...5:128 1]
Jul 09 12:12:27 VIGT01-101.res01.ads.ooe.local multipathd[19277]: 3600a098038303561325d474f4b597538: event checker started
Jul 09 12:12:27 VIGT01-101.res01.ads.ooe.local multipathd[19277]: 3600a098038303561325d474f4b597539: event checker started
Jul 09 12:12:27 VIGT01-101.res01.ads.ooe.local multipathd[19277]: san_disk1: event checker started
Jul 09 12:12:27 VIGT01-101.res01.ads.ooe.local multipathd[19277]: path checkers start up
Hint: Some lines were ellipsized, use -l to show in full.
  • Why multipath could hide the sdx devices? – c4f4t0r May 28 at 23:46
0

It's OK. The underlying devices are not being hidden in any way.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.