From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mikhail Shevyakov Subject: Wrong behaviour of multipathing on Active/Passive storage array Date: Mon, 11 Jul 2011 19:34:46 +0400 Message-ID: <1310398486.6249.209.camel@mi> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============6137548818621578172==" Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: dm-devel@redhat.com List-Id: dm-devel.ids --===============6137548818621578172== Content-Type: multipart/alternative; boundary="=-aFLt3tJlmutzrRFWLFJd" --=-aFLt3tJlmutzrRFWLFJd Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Hello! I try to configure multipathing for Active/Passive storage and I have a problem with this: when paths are switched (Active->Passive, Passive->Active) all read/write operations are suspended. When paths switches back read/write resumes. Following is the configuration: # less /etc/multipath.conf defaults { user_friendly_names yes prio alua path_checker tur no_path_retry 10 fast_io_fail_tmo 5 polling_interval 10 selector "round-robin 0" path_grouping_policy multibus rr_min_io 100 failback immediate } # multipath -ll mpathb (0AvroRAIDDVAS 000000000000000097f62ae1) dm-0 AvroRAID,DVAS size=683G features='1 queue_if_no_path' hwhandler='0' wp=rw `-+- policy='round-robin 0' prio=5 status=active |- 7:0:0:0 sdc 8:32 active ghost running `- 9:0:0:0 sdd 8:48 active ready running This is output of st_turs: # sg_turs -v /dev/sdd test unit ready cdb: 00 00 00 00 00 00 # sg_turs -v /dev/sdc test unit ready cdb: 00 00 00 00 00 00 test unit ready: Fixed format, current; Sense key: Not Ready Additional sense: Logical unit not accessible, target port in standby state Info fld=0x0 [0] device not ready And REPORT TARGET PORT GROUPS output: #sg_rtpg /dev/sdd Report target port groups: target port group id : 0x1 , Pref=1 target port group asymmetric access state : 0x00 T_SUP : 0, O_SUP : 0, U_SUP : 1, S_SUP : 1, AN_SUP : 0, AO_SUP : 1 status code : 0x02 vendor unique status : 0x00 target port count : 02 Relative target port ids: 0x01 0x02 #sg_rtpg /dev/sdc Report target port groups: target port group id : 0x2 , Pref=0 target port group asymmetric access state : 0x02 T_SUP : 0, O_SUP : 0, U_SUP : 1, S_SUP : 1, AN_SUP : 0, AO_SUP : 1 status code : 0x02 vendor unique status : 0x00 target port count : 04 Relative target port ids: 0x01 0x02 0x03 0x04 I used dd to write on the dm device: #dd if=/dev/zero of=/dev/dm-0 oflag=direct bs=1M Everything works fine untill paths are switched. dd stops, turs output: # sg_turs -v /dev/sdd test unit ready cdb: 00 00 00 00 00 00 # sg_turs -v /dev/sdc test unit ready cdb: 00 00 00 00 00 00 test unit ready: Fixed format, current; Sense key: Not Ready Additional sense: Logical unit not accessible, target port in standby state Info fld=0x0 [0] device not ready REPORT TARGET PORT GROUPS output: # sg_rtpg /dev/sdd Report target port groups: target port group id : 0x1 , Pref=0 target port group asymmetric access state : 0x02 T_SUP : 0, O_SUP : 0, U_SUP : 1, S_SUP : 1, AN_SUP : 0, AO_SUP : 1 status code : 0x02 vendor unique status : 0x00 target port count : 02 Relative target port ids: 0x01 0x02 # sg_rtpg /dev/sdc Report target port groups: target port group id : 0x2 , Pref=1 target port group asymmetric access state : 0x00 T_SUP : 0, O_SUP : 0, U_SUP : 1, S_SUP : 1, AN_SUP : 0, AO_SUP : 1 status code : 0x02 vendor unique status : 0x00 target port count : 04 Relative target port ids: 0x01 0x02 0x03 0x04 As you can see paths' states are switched.Output of multipath: # multipath -ll mpathb (0AvroRAIDDVAS 000000000000000097f62ae1) dm-0 AvroRAID,DVAS size=683G features='1 queue_if_no_path' hwhandler='0' wp=rw `-+- policy='round-robin 0' prio=5 status=enabled |- 7:0:0:0 sdc 8:32 failed ready running `- 9:0:0:0 sdd 8:48 failed ghost running So states of the paths are changed but multipath for some reason fails both paths. Is something wrong with my config or is it a bug in multipath? Could you help me with this problem? Regards Mikhail Shevyakov --=-aFLt3tJlmutzrRFWLFJd Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: 7bit Hello!
I try to configure multipathing for Active/Passive storage and I have a problem with this:
when paths are switched (Active->Passive, Passive->Active) all read/write operations
are suspended. When paths switches back read/write resumes.
Following is the configuration:

# less /etc/multipath.conf 
defaults {
user_friendly_names yes
prio alua
path_checker tur
no_path_retry 10
fast_io_fail_tmo 5
polling_interval        10
selector                "round-robin 0"
path_grouping_policy    multibus
rr_min_io               100
failback                immediate
}


# multipath -ll
mpathb (0AvroRAIDDVAS            000000000000000097f62ae1) dm-0 AvroRAID,DVAS
size=683G features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=5 status=active
  |- 7:0:0:0 sdc 8:32 active ghost  running
  `- 9:0:0:0 sdd 8:48 active ready  running

This is output of st_turs:

# sg_turs -v /dev/sdd
    test unit ready cdb: 00 00 00 00 00 00 
# sg_turs -v /dev/sdc
    test unit ready cdb: 00 00 00 00 00 00 
test unit ready:  Fixed format, current;  Sense key: Not Ready
 Additional sense: Logical unit not accessible, target port in standby state
  Info fld=0x0 [0] 
device not ready

And REPORT TARGET PORT GROUPS output:

#sg_rtpg /dev/sdd 
Report target port groups:
  target port group id : 0x1 , Pref=1
    target port group asymmetric access state : 0x00
    T_SUP : 0, O_SUP : 0, U_SUP : 1, S_SUP : 1, AN_SUP : 0, AO_SUP : 1
    status code : 0x02
    vendor unique status : 0x00
    target port count : 02
    Relative target port ids:
      0x01
      0x02
#sg_rtpg /dev/sdc
Report target port groups:
  target port group id : 0x2 , Pref=0
    target port group asymmetric access state : 0x02
    T_SUP : 0, O_SUP : 0, U_SUP : 1, S_SUP : 1, AN_SUP : 0, AO_SUP : 1
    status code : 0x02
    vendor unique status : 0x00
    target port count : 04
    Relative target port ids:
      0x01
      0x02
      0x03
      0x04

I used dd to write on the dm device:

#dd if=/dev/zero of=/dev/dm-0 oflag=direct bs=1M

Everything works fine untill paths are switched. dd stops, turs output:

# sg_turs -v /dev/sdd
    test unit ready cdb: 00 00 00 00 00 00 
# sg_turs -v /dev/sdc
    test unit ready cdb: 00 00 00 00 00 00 
test unit ready:  Fixed format, current;  Sense key: Not Ready
 Additional sense: Logical unit not accessible, target port in standby state
  Info fld=0x0 [0] 
device not ready
 
REPORT TARGET PORT GROUPS output:

# sg_rtpg /dev/sdd 
Report target port groups:
  target port group id : 0x1 , Pref=0
    target port group asymmetric access state : 0x02
    T_SUP : 0, O_SUP : 0, U_SUP : 1, S_SUP : 1, AN_SUP : 0, AO_SUP : 1
    status code : 0x02
    vendor unique status : 0x00
    target port count : 02
    Relative target port ids:
      0x01
      0x02
# sg_rtpg /dev/sdc
Report target port groups:
  target port group id : 0x2 , Pref=1
    target port group asymmetric access state : 0x00
    T_SUP : 0, O_SUP : 0, U_SUP : 1, S_SUP : 1, AN_SUP : 0, AO_SUP : 1
    status code : 0x02
    vendor unique status : 0x00
    target port count : 04
    Relative target port ids:
      0x01                                                                                                                                                                                                                                   
      0x02                                                                                                                                                                                                                                   
      0x03                                                                                                                                                                                                                                   
      0x04

As you can see paths' states are switched.Output of multipath:

# multipath -ll
mpathb (0AvroRAIDDVAS            000000000000000097f62ae1) dm-0 AvroRAID,DVAS
size=683G features='1 queue_if_no_path' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=5 status=enabled
  |- 7:0:0:0 sdc 8:32 failed ready  running
  `- 9:0:0:0 sdd 8:48 failed ghost  running


So states of the paths are changed but multipath for some reason fails both paths.
Is something wrong with my config or is it a bug in multipath?
Could you help me with this problem?

Regards
Mikhail Shevyakov
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