[CentOS] multipath

Paras pradhan pradhanparas at gmail.com
Tue Jan 12 19:02:09 UTC 2010


Can anybody tell me if my multipath o/p is fine?

I have a active/active setup and when I unplug the FC SAN cable on one of
the ports of my HBA my host is being un responsive and need to reboot it.

When I do

multipath -ll

I can see:

[root at cvprd2 etc]# multipath -ll
mpath2 (360060e8004770d000000770d0000018c) dm-1 HITACHI,OPEN-V*10
[size=335G][features=1 queue_if_no_path][hwhandler=0][rw]
\_ round-robin 0 [prio=8][active]
 \_ 6:0:0:1     sdc 8:32  [active][ready]
 \_ 6:0:0:16385 sde 8:64  [active][ready]
 \_ 6:0:0:32769 sdg 8:96  [active][ready]
 \_ 6:0:0:49153 sdi 8:128 [active][ready]
 \_ 5:0:0:1     sdk 8:160 [active][ready]
 \_ 5:0:0:16385 sdm 8:192 [active][ready]
 \_ 5:0:0:32769 sdo 8:224 [active][ready]
 \_ 5:0:0:49153 sdq 65:0  [active][ready]
mpath1 (360060e8004770d000000770d00000154) dm-0 HITACHI,OPEN-V*9
[size=301G][features=1 queue_if_no_path][hwhandler=0][rw]
\_ round-robin 0 [prio=8][active]
 \_ 6:0:0:0     sdb 8:16  [active][ready]
 \_ 6:0:0:16384 sdd 8:48  [active][ready]
 \_ 6:0:0:32768 sdf 8:80  [active][ready]
 \_ 6:0:0:49152 sdh 8:112 [active][ready]
 \_ 5:0:0:0     sdj 8:144 [active][ready]
 \_ 5:0:0:16384 sdl 8:176 [active][ready]
 \_ 5:0:0:32768 sdn 8:208 [active][ready]
 \_ 5:0:0:49152 sdp 8:240 [active][ready]
[root at cvprd2 etc]#


--

But when I do "multipath -v2" i donot see anything..


[root at cvprd2 etc]# multipath -v2
[root at cvprd2 etc]#


--

My multipath.conf is as below:

[root at cvprd1 etc]# more multipath.conf
# This is a basic configuration file with some examples, for device mapper
# multipath.
# For a complete list of the default configuration values, see
# /usr/share/doc/device-mapper-multipath-0.4.7/multipath.conf.defaults
# For a list of configuration options with descriptions, see
# /usr/share/doc/device-mapper-multipath-0.4.7/multipath.conf.annotated


# Blacklist all devices by default. Remove this to enable multipathing
# on the default devices.
blacklist {
        devnode "^sda"
}

## Use user friendly names, instead of using WWIDs as names.
defaults {
user_friendly_names yes
polling_interval 5
no_path_retry 3
failover immediate
path_grouping_policy multibus
rr_weight priorities
path_checker readsector0
}
devices {
        device {
                vendor                  "HITACHI"
                product                 "OPEN-V"
                path_grouping_policy    multibus
                path_checker            readsector0
                getuid_callout          "/sbin/scsi_id -g -u -p0x80 -s
/block/%n"
        }
}
[root at cvprd1 etc]#


Thanks !
Paras




On Tue, Jan 12, 2010 at 10:37 AM, Paras pradhan <pradhanparas at gmail.com>wrote:

> Upgrding the kernel to 2.6.18-164.10.1.el5xen brought back /dev/dm-* and
> now multipath -ll has the ouput.
>
> I am curious about what has caused the lost of /dev/dm* in my previous
> kernel.
>
> Any ideas?
>
> Paras.
>
>
> On Mon, Jan 11, 2010 at 8:09 PM, Paras pradhan <pradhanparas at gmail.com>wrote:
>
>> Yes every thing's loaded.
>>
>> Here is the output:
>>
>> [root at cvprd1 ~]# lsmod | grep dm
>> dm_round_robin         36801  0
>> rdma_cm                68565  1 ib_iser
>> ib_cm                  73449  1 rdma_cm
>> iw_cm                  43465  1 rdma_cm
>> ib_sa                  75209  2 rdma_cm,ib_cm
>> ib_core               105157  6 ib_iser,rdma_cm,ib_cm,iw_cm,ib_sa,ib_mad
>> ib_addr                41929  1 rdma_cm
>> dm_multipath           56153  1 dm_round_robin
>> scsi_dh                41665  1 dm_multipath
>> dm_raid45              99401  0
>> dm_message             36289  1 dm_raid45
>> dm_region_hash         46273  1 dm_raid45
>> dm_mem_cache           39489  1 dm_raid45
>> dm_snapshot            52105  0
>> dm_zero                35265  0
>> dm_mirror              54737  0
>> dm_log                 44993  3 dm_raid45,dm_region_hash,dm_mirror
>> dm_mod                101521  11
>> dm_multipath,dm_raid45,dm_snapshot,dm_zero,dm_mirror,dm_log
>>
>>
>>
>> Thanks
>> Paras.
>>
>>
>>
>>
>> On Mon, Jan 11, 2010 at 6:33 PM, nate <centos at linuxpowered.net> wrote:
>>
>>> Paras pradhan wrote:
>>> > Hi.
>>> >
>>> > Somehow I do not see any out put using multipath -l or multipath -ll .
>>> But I
>>> > can see using dry run ie multipath -d.
>>> >
>>> > Also I do not see /dev/dm-*
>>> >
>>> > It was there before. How do I re claim it.
>>>
>>> Are the modules loaded?
>>>
>>> [root at dc1-mysql001a:~]# lsmod | grep dm
>>> dm_zero                35265  0
>>> dm_mirror              60617  0
>>> dm_round_robin         36801  1
>>> dm_multipath           52945  2 dm_round_robin
>>> dm_mod                 99737  17 dm_zero,dm_mirror,dm_multipath
>>> [root at dc1-mysql001a:~]# multipath -l
>>> 350002ac0006a0714dm-1 3PARdata,VV
>>> [size=1.0T][features=0][hwhandler=0]
>>> \_ round-robin 0 [prio=0][active]
>>>  \_ 1:0:0:3 sdc 8:32  [active][undef]
>>>  \_ 1:0:1:3 sde 8:64  [active][undef]
>>>  \_ 2:0:0:3 sdg 8:96  [active][undef]
>>>  \_ 2:0:1:3 sdi 8:128 [active][undef]
>>> 350002ac000790714dm-0 3PARdata,VV
>>> [size=2.0T][features=0][hwhandler=0]
>>> \_ round-robin 0 [prio=0][active]
>>>  \_ 1:0:0:2 sdb 8:16  [active][undef]
>>>  \_ 1:0:1:2 sdd 8:48  [active][undef]
>>>  \_ 2:0:0:2 sdf 8:80  [active][undef]
>>>  \_ 2:0:1:2 sdh 8:112 [active][undef]
>>>
>>>
>>>
>>> nate
>>>
>>>
>>> _______________________________________________
>>> CentOS mailing list
>>> CentOS at centos.org
>>> http://lists.centos.org/mailman/listinfo/centos
>>>
>>
>>
>
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