[dm-devel] Consult about revert PATH_GOST in tur_check

[Suoben]

Hi Reinecke
Description of problem:

1.       As network issue, System is disconnected from the Storage.

2.       When network recover, we found two path are in "ghost" state

3.       We need to register PRKEY. But it failed when register PRKEY through the two "ghost" path.

4.       It seems wired, maybe the Storage hardware have issue. but now we want to work around this issue in multipath first.

5.       Our work around solution is as following

a)         Revert this patch "Return 'ghost' state when port is in standby"(5da642ff71254ecda685e82c681e78cab4c75b87)

b)         Then all PATH_GHOST will be treated as PATH_FAILED

c)         and multipath will only register PRKEY by PATH_UP pathes.
Questions:
so we want to consult whether there some potential issue after we revert the patch?
We know it will lead to some performance and reliability loss. We mainly worry about
whether there are some potential functional and fundamental issues?
Thanks a lot.

Environment Info:

mpathal (2e0176ad6309077166c9ce90033bfa248_1) dm-2 TestSAN

size=20G features='1 queue_if_no_path' hwhandler='0' wp=rw

`-+- policy='round-robin 0' prio=50 status=active

  |- 8:0:5:1 sddg 8:96  active ready running

  `- 9:0:6:1 sdwh 12:112 active ready running

`-+- policy='round-robin 0' prio=10 status=enabled

  |- 10:0:5:1 sdga 21:96  active ready running

  `- 11:0:6:1 sdhb 81:112 active ready running

`-+- policy='round-robin 0' prio=1 status= enabled

  |- 12:0:5:1 sdgj 15:6  active ghost running

  `- 13:0:6:1 sdhk 16:112 active ghost running


defaults {
                   path_checker            tur
                   no_path_retry           18
                   path_grouping_policy    group_by_prio
                   prio                    const
                   deferred_remove         yes
                   uid_attribute           "ID_SERIAL"
                   reassign_maps           no
                   failback                immediate
                   log_checker_err         once
}

devices {
      device {
       vendor                              "TestSAN"
       product                             "LU"
       path_grouping_policy       group_by_prio
       no_path_retry                   30
       prio                                    alua
       path_checker                     tur
       path_selector                    "round-robin 0"
       hardware_handler               "0"
       failback                                15
        }
}

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