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4 Replies Latest reply: Aug 6, 2012 8:25 AM by 898553 RSS

Help with Multipath

691078 Newbie
Currently Being Moderated
Hi All,

When I execute multipath -ll command that time display only 3 path (orafra2,oradata2 and oradata1), not display other 2 path (orafra1 and data1). I have configure 5 path in /etc/multipath.conf file. What is the reason behind it. Please help me.

Please find below some output for help:

###################################################

[root@reuxeuls003 ~]# multipath -ll
orafra2 (360060160a71e2100de29aae7f4f9de11) dm-10 DGC,RAID 10
size=200G features='1 queue_if_no_path' hwhandler='1 emc' wp=rw
|-+- policy='round-robin 0' prio=1 status=active
| |- 1:0:1:3 sds 65:32 active ready running
| `- 0:0:1:3 sdi 8:128 active ready running
`-+- policy='round-robin 0' prio=0 status=enabled
|- 1:0:0:3 sdn 8:208 active ready running
`- 0:0:0:3 sdd 8:48 active ready running
oradata2 (360060160951e2100ccc3b4800798df11) dm-9 DGC,RAID 10
size=200G features='1 queue_if_no_path' hwhandler='1 emc' wp=rw
|-+- policy='round-robin 0' prio=1 status=active
| |- 1:0:0:4 sdo 8:224 active ready running
| `- 0:0:0:4 sde 8:64 active ready running
`-+- policy='round-robin 0' prio=0 status=enabled
|- 1:0:1:4 sdt 65:48 active ready running
`- 0:0:1:4 sdj 8:144 active ready running
oradata1 (360060160a71e210002263e3fbde0dd11) dm-11 DGC,RAID 10
size=300G features='1 queue_if_no_path' hwhandler='1 emc' wp=rw
|-+- policy='round-robin 0' prio=1 status=active
| |- 1:0:0:0 sdk 8:160 active ready running
| `- 0:0:0:0 sda 8:0 active ready running
`-+- policy='round-robin 0' prio=0 status=enabled
|- 1:0:1:0 sdp 8:240 active ready running
`- 0:0:1:0 sdf 8:80 active ready running

####################################################

Output of multipath.conf file:

##################################################

[root@reuxeuls003 ~]# egrep -v "^#|^$" /etc/multipath.conf
defaults {
user_friendly_names yes
}
multipaths {
multipath {
wwid 360060160a71e210002263e3fbde0dd11
alias oradata1
}
multipath {
wwid 360060160951e2100ccc3b4800798df11
alias oradata2
}
multipath {
wwid 360060160a71e21009a4a0a180fe7dd11
alias orafra1
}
multipath {
wwid 360060160a71e210080492a4f0fe7dd11
alias data1
}
multipath {
wwid 360060160a71e2100de29aae7f4f9de11
alias orafra2
}
}
[root@reuxeuls003 ~]#

####################################################

Output of /var/log/messages :

####################################################


[root@reuxeuls003 ~]# tail -10f /var/log/messages
Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: table: 253:13: multipath: error getting device
Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: ioctl: error adding target to table
Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: multipath emc: long trespass command will be send
Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: multipath emc: honor reservation bit will not be set (default)
Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: table: 253:13: multipath: error getting device
Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: ioctl: error adding target to table
Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: multipath emc: long trespass command will be send
Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: multipath emc: honor reservation bit will not be set (default)
Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: table: 253:13: multipath: error getting device
Aug 3 09:52:16 reuxeuls003 kernel: device-mapper: ioctl: error adding target to table

####################################################################

Please help me.
Thanks in advance.
  • 1. Re: Help with Multipath
    BillyVerreynne Oracle ACE
    Currently Being Moderated
    Have you modified +/etc/udev/rules.d/40-multipath.rules+ ?

    What does the kernel say when discovering these EMC LUNs (prior to multipath loading)?

    What I/O fabric layer are you using? Fibre? Ethernet? SRP? And it would seem that EMC is being used (from the hwhandler output) - is Powerpath loaded and in use?

    Multipath does not do the device discovery and enumeration. That is done prior when the kernel boots and the I/O fabric layer driver is loaded. Multipath attempts to determine what the I/O paths are, which devices refer to the same WWID, and then (if whitelisted) map these to a single logical multipath device.

    So if multipath runs in a device error of sorts (as per your kernel log) - that error very likely comes from deeper down the driver stack.

    Can you flush and rerun multipath and post the output? E.g.
    // devices may not be in use
    [root@reuxeuls003 ~]# multipath -F
    
    // run multipath discovery with verbosity at level 3
    [root@reuxeuls003 ~]# multipath -v3
  • 2. Re: Help with Multipath
    691078 Newbie
    Currently Being Moderated
    Hi,

    I am not change /etc/udev/rules.d/40-multipath.rules file.
    Also I am not sending the output of "multipath -v3". Because output is too long.
  • 3. Re: Help with Multipath
    BillyVerreynne Oracle ACE
    Currently Being Moderated
    Well, then you need to go line-by-line through that verbose output and see what the errors multipath runs into, trying to use the problem I/O paths (scsi devices).

    Or open a SR (service request) with Oracle to investigate the error - assuming you have an OL support agreement and a CSI number.
  • 4. Re: Help with Multipath
    898553 Newbie
    Currently Being Moderated
    I'm assuming this is on a CLARiiON since it's displaying DGC?

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