[dm-devel] multipath disk vendor/model in lsblk and sysfs

[Russell Weber]

I’ve noticed that multipath devices don’t report manufacturer or model into
lsblk, but they do report model and vendor when running the multipath
utility as “multipath –ll”.
See following example (Yes I realize my disks have failed horribly… I was
testing something else at the time.).  I have highlighted important areas.

> multipath -ll
mpaths (26664303464626366) dm-3 FUSIONIO,ION LUN


size=93G features='3 queue_if_no_path pg_init_retries 50' hwhandler='1
alua'
wp=rw


|-+- policy='queue-length 0' prio=0
status=enabled


| |- 8:0:3:2 sdbg 67:160 failed faulty
running


| |- 7:0:3:2 sdas 66:192 failed faulty
running


| `- 7:0:2:2 sdac 65:192 failed faulty
running


|-+- policy='queue-length 0' prio=0
status=enabled


| |- 7:0:1:2 sds  65:32  failed faulty
running


| `- 8:0:0:2 sdh  8:112  failed faulty running


|-+- policy='queue-length 0' prio=0
status=enabled


| |- 7:0:0:2 sdc  8:32   failed faulty
running


| `- 8:0:1:2 sdab 65:176 failed faulty
running


`-+- policy='queue-length 0' prio=0
status=enabled


  `- 8:0:2:2 sdar 66:176 failed faulty
running


> lsblk -s -o kname,type,model,vendor
/dev/dm-3


KNAME TYPE  MODEL
VENDOR


dm-3  mpath


                                                  .

sdc   disk  ION LUN          FUSIONIO


sdh   disk  ION LUN
FUSIONIO


sds   disk  ION LUN
FUSIONIO


sdab  disk  ION LUN
FUSIONIO


sdac  disk  ION LUN
FUSIONIO


sdbg  disk  ION LUN
FUSIONIO


sdar  disk  ION LUN
FUSIONIO


sdas  disk  ION LUN
FUSIONIO




I am assuming that this is because each multipath device is missing a sysfs
endpoint for lsblk to read which contains the pertinent model and device
information.  It would appear that the underlying slave block devices do
however have the information.


> cat
/sys/class/block/dm-3/slaves/*/device/model


ION
LUN


ION
LUN


ION LUN


ION
LUN


ION
LUN


ION
LUN


ION
LUN


I’ve been trying to find the best place in the code to add the feature
myself, but with limited experience, time and other obligations my time for
adding additional sysfs endpionts to make lsblk work correctly has been
quickly spent up.  Maybe I’m going about this the wrong way, but with time
short, I wasn’t sure what the best course of action was for subbmitting a
feature request or line of questioning of how to add the additional sysfs
endpionts without breaking linux as a whole by myself as a novice kernel
developer.

Is this something I should even be worrying about, IE. Working as
designed?  If so, what is the policy on listing the model and volume of a
multipath disk?

Should this issue end up as a fix in lsblk, or the multipath device
endpoint in sysfs?
Who should I be senging email to about making this a feature request?
If I truly have to make the fix myself, any advice on where I should be
starting in the multipath code or lsblk code respectivly?

Also, apologies in advance if I am bugging the wrong list about this.

Russell Weber
Software Support and Quality engineer

One Stop Systems
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