Bug 1145442

This is an example of someone else who was similarly frustrated by the output format, however this utility doesn't appear to have been maintained and doesn't work on our systems:

http://www.tablespace.net/ppath/index.html

This seems mostly handled by the

# multipathd show maps format

and

# multipathd show paths format

commands. However these commands print headers, and add spaces for padding that can make parsing harder.  I've implemented versions of these commands called

# multipathd raw maps format

and

# multipathd raw paths format

that just print the data you ask for in the way you ask for it in the format string.  I can backport this to make parsing easier.

Thanks for looking into this.

Interesting, I had no idea until now that 'multipathd' had gained some parameters to do anything other than start the daemon.  Doesn't this defeat the purpose of the 'multipath' command somewhat?  Will that be deprecated?

I fail to find the content of the $format parameter documented anywhere in the man pages, am I missing something obvious?

The 'raw' option would indeed be useful, however parsing out padding space and headings is relatively trivial - it was the completely variable output formats of 'multipath -ll' that previously presented a real challenge.

(In reply to Scott Rochford from comment #4)
> Thanks for looking into this.
> 
> Interesting, I had no idea until now that 'multipathd' had gained some
> parameters to do anything other than start the daemon.  Doesn't this defeat
> the purpose of the 'multipath' command somewhat?  Will that be deprecated?

Possibly in the future, but there are no immediate plans to do so.

> I fail to find the content of the $format parameter documented anywhere in
> the man pages, am I missing something obvious?

More like something obscure. The format string is just a string using various wildcards to request the information.  You can see the supported wildcards with

# multipathd show wildcards

For instance, you could show all the multipath map information from your example above with:

# multipathd show maps format "%n %w %d %s"

Unfortunately, RHEL6 has many fewer wildcards than RHEL7, and there isn't one to list what multipath device a path belongs to, so you have to compare wwids, but you can get the path information from your example by running

# multipathd show paths format "%w %i %d %t %o %T"

> The 'raw' option would indeed be useful, however parsing out padding space
> and headings is relatively trivial - it was the completely variable output
> formats of 'multipath -ll' that previously presented a real challenge.

So, I suppose this bug should be used to both add the raw option, and backport the additional wildcards.

> More like something obscure. The format string is just a string using 
> various wildcards to request the information.  You can see the supported 
> wildcards with
> # multipathd show wildcards

Sorry, somehow I read straight past that one on the man page without seeing it.

> So, I suppose this bug should be used to both add the raw option, and 
> backport the additional wildcards.

Yes, both would be appreciated, thanks.

The fix for this bug caused a coverity issue. I've fixed the patch to avoid this issue.

1)
[root@storageqe-18 ~]# multipathd show paths format "%w %i %d %t %o %T"
uuid                              hcil    dev dm_st  dev_st  chk_st
360a98000324669436c2b45666c567942 4:0:1:0 sdj active running ready 
360a98000324669436c2b45666c567942 5:0:1:0 sdz active running ready 
360a98000324669436c2b45666c567942 4:0:0:0 sda active running ready 
360a98000324669436c2b45666c567942 5:0:0:0 sds active running ready 

[root@storageqe-18 ~]# multipathd show paths raw format "%w %i %d %t %o %T"
360a98000324669436c2b45666c567942 4:0:1:0 sdj active running ready
360a98000324669436c2b45666c567942 5:0:1:0 sdz active running ready
360a98000324669436c2b45666c567942 4:0:0:0 sda active running ready
360a98000324669436c2b45666c567942 5:0:0:0 sds active running ready

2)
[root@storageqe-18 ~]# multipathd show maps format "%n %w %d %s"
name   uuid                              sysfs vend/prod/rev
mpathc 360a98000324669436c2b45666c567942 dm-0  NETAPP,LUN   

[root@storageqe-18 ~]# multipathd show maps raw format "%n %w %d %s"
mpathc 360a98000324669436c2b45666c567942 dm-0 NETAPP,LUN


From step 1  and step 2, # multipathd show paths raw format $FMT
and
# multipathd show maps raw format $FMT
work the same as the non-raw versions, but without headers and extra padding being added to the output.


3)
[root@storageqe-18 ~]# multipathd show paths format "%z %m %N %n %R %r %a"
serial       multipath host WWNN          target WWNN        host WWPN          target WWPN        host adapter
2FiCl+EflVyB mpathc    0x20000000c9a02834 0x500a0980891b8dc5 0x10000000c9a02834 0x500a0982991b8dc5 0000:00:06.0
2FiCl+EflVyB mpathc    0x20000000c9a02835 0x500a0980891b8dc5 0x10000000c9a02835 0x500a0981991b8dc5 0000:00:06.0
2FiCl+EflVyB mpathc    0x20000000c9a02834 0x500a0980891b8dc5 0x10000000c9a02834 0x500a0982891b8dc5 0000:00:06.0
2FiCl+EflVyB mpathc    0x20000000c9a02835 0x500a0980891b8dc5 0x10000000c9a02835 0x500a0981891b8dc5 0000:00:06.0

[root@storageqe-18 ~]# multipathd show paths raw format "%z %m %N %n %R %r %a"
2FiCl+EflVyB mpathc 0x20000000c9a02834 0x500a0980891b8dc5 0x10000000c9a02834 0x500a0982991b8dc5 0000:00:06.0
2FiCl+EflVyB mpathc 0x20000000c9a02835 0x500a0980891b8dc5 0x10000000c9a02835 0x500a0981991b8dc5 0000:00:06.0
2FiCl+EflVyB mpathc 0x20000000c9a02834 0x500a0980891b8dc5 0x10000000c9a02834 0x500a0982891b8dc5 0000:00:06.0
2FiCl+EflVyB mpathc 0x20000000c9a02835 0x500a0980891b8dc5 0x10000000c9a02835 0x500a0981891b8dc5 0000:00:06.0

4)
[root@storageqe-18 ~]# multipathd show paths raw format %z
2FiCl+EflVyB
2FiCl+EflVyB
2FiCl+EflVyB
2FiCl+EflVyB
[root@storageqe-18 ~]# multipathd show paths raw format %m
mpathc
mpathc
mpathc
mpathc
[root@storageqe-18 ~]# multipathd show paths raw format %N
0x20000000c9a02834
0x20000000c9a02835
0x20000000c9a02834
0x20000000c9a02835
[root@storageqe-18 ~]# multipathd show paths raw format %n
0x500a0980891b8dc5
0x500a0980891b8dc5
0x500a0980891b8dc5
0x500a0980891b8dc5
[root@storageqe-18 ~]# multipathd show paths raw format %R
0x10000000c9a02834
0x10000000c9a02835
0x10000000c9a02834
0x10000000c9a02835
[root@storageqe-18 ~]# multipathd show paths raw format %r
0x500a0982991b8dc5
0x500a0981991b8dc5
0x500a0982891b8dc5
0x500a0981891b8dc5
[root@storageqe-18 ~]# multipathd show paths raw format %a
0000:00:06.0
0000:00:06.0
0000:00:06.0
0000:00:06.0

From step 3 and step 4, the %z, %m, %N, %n, %R, %r, and %a path format wildcards work as expected.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2016-0777.html