[PVE-User] multipath problem on IBM 1746... problem (?)

[dea]

Hi all !

I've a big problem on multipath && SAS SAN IBM (ds3xxx series, IBM 1746 FAStT).
The multipath.conf is correct (I think) and the device works !!!
But:

1) path ready and path ghost commute continuously:
***********
root at proxmox1:~# multipath -ll
mpath0 (360080e50002f7372000001ee50ed10d9) dm-1 IBM,1746      FAStT
size=1.6T features='3 queue_if_no_path pg_init_retries 50' hwhandler='1 rdac'
wp=rw
`-+- policy='round-robin 0' prio=2 status=active
  |- 7:0:0:0 sda 8:0  active ghost running
  `- 8:0:0:0 sdd 8:48 active ready running
***********

***********
root at proxmox1:~# multipath -ll
mpath0 (360080e50002f7372000001ee50ed10d9) dm-1 IBM,1746      FAStT
size=1.6T features='3 queue_if_no_path pg_init_retries 50' hwhandler='1 rdac'
wp=rw
`-+- policy='round-robin 0' prio=2 status=active
  |- 7:0:0:0 sda 8:0  active ready running
  `- 8:0:0:0 sdd 8:48 active ghost running
***********

2) The SAN report a warning (preferred path changed)

3) Many error in syslog:
***********
Jan 25 11:35:21 proxmox1 kernel: sd 8:0:0:0: rdac: array Rugger, ctlr 1,
queueing MODE_SELECT command
Jan 25 11:35:21 proxmox1 kernel: sd 8:0:0:0: rdac: array Rugger, ctlr 1,
MODE_SELECT completed
Jan 25 11:35:27 proxmox1 kernel: sd 7:0:0:0: [sda] Result: hostbyte=DID_OK
driverbyte=DRIVER_SENSE
Jan 25 11:35:27 proxmox1 kernel: sd 7:0:0:0: [sda] Sense Key : Illegal Request
[current] 
Jan 25 11:35:27 proxmox1 kernel: sd 7:0:0:0: [sda] <<vendor>> ASC=0x94
ASCQ=0x1ASC=0x94 ASCQ=0x1
Jan 25 11:35:27 proxmox1 kernel: sd 7:0:0:0: [sda] CDB: Read(10): 28 00 d1 67
83 80 00 00 08 00
Jan 25 11:35:27 proxmox1 kernel: device-mapper: multipath: Failing path 8:0.
Jan 25 11:35:29 proxmox1 kernel: sd 7:0:0:0: rdac: array Rugger, ctlr 0,
queueing MODE_SELECT command
Jan 25 11:35:29 proxmox1 kernel: sd 7:0:0:0: rdac: array Rugger, ctlr 0,
MODE_SELECT completed
***********

I've just modify LVM configuration to skip direct accedd to sdX drive and
works fine.

This is my multipath.conf
*******
devices {
device {
    vendor "IBM"
    product "1746"
    path_grouping_policy group_by_prio
    path_selector "round-robin 0"
    path_checker rdac
    features "2 pg_init_retries 50"
    hardware_handler "1 rdac"
    prio_callout "/sbin/mpath_prio_rdac /dev/%n"
    failback immediate    
    rr_weight uniform
    no_path_retry 15
    rr_min_io 1000
}
}

blacklist {
    wwid *
}

blacklist_exceptions {
    wwid "360080e50002f7372000001ee50ed10d9"
}

multipaths {
multipath {
    wwid "360080e50002f7372000001ee50ed10d9"
    alias mpath0
}
}

*******

Any idea ???

Very thanks

Luca