[dm-devel] failover does not work with rdac device handler

[Moger, Babu]

Hi Chandra,

All the dh_state values show "rdac".  I have cut pasted the output below.

I am seeing the following error messages when I tried to failover.

        Oct  6 13:50:01 localhost multipathd: 8:96: reinstated
        Oct  6 13:50:01 localhost kernel: device-mapper: multipath: Cannot              failover device because scsi_dh_rdac was not loaded.
        Oct  6 13:50:01 localhost kernel: device-mapper: multipath: Failing             path 8:96.
        Oct  6 13:50:01 localhost kernel: device-mapper: multipath: Could not           failover device. Error 15.
        Oct  6 13:50:01 localhost multipathd: 8:96: mark as failed


Output of # multipath -ll

        mpath2 (3600a0b80000f6a7d000080454714d058) dm-2 LSI,INF-01-00
        [size=10G][features=1 queue_if_no_path][hwhandler=1 rdac][rw]
        \_ round-robin 0 [prio=6][active]
         \_ 3:0:0:2 sdf 8:80  [active][ready]
         \_ 3:0:2:2 sdl 8:176 [active][ready]
        \_ round-robin 0 [prio=0][enabled]
         \_ 3:0:1:2 sdi 8:128 [active][ghost]
         \_ 3:0:3:2 sdo 8:224 [active][ghost]


dh_state values.

        #cat /sys/block/sdf/device/dh_state
        rdac

        #cat /sys/block/sdl/device/dh_state
        rdac

        #cat /sys/block/sdi/device/dh_state
        rdac

        # cat /sys/block/sdo/device/dh_state
        rdac

 Please let me know what you think.
 Note (Kernel version 2.6.27-rc7 and multipath-tools v0.4.8)

Thanks
Babu Moger

-----Original Message-----
From: Moger, Babu
Sent: Friday, October 03, 2008 10:35 PM
To: sekharan at us.ibm.com
Cc: device-mapper development; linux-scsi at vger.kernel.org
Subject: RE: [dm-devel] failover does not work with rdac device handler

Thanks Chandra for the response..

That is the good news. So, we do not have to change the kernel  code everytime we want to support the new product.

I will do the steps you mentioned first thing on Monday and reply your back.

Thanks
Babu Moger

________________________________________
From: Chandra Seetharaman [sekharan at us.ibm.com]
Sent: Friday, October 03, 2008 7:50 PM
To: Moger, Babu
Cc: device-mapper development; linux-scsi at vger.kernel.org
Subject: Re: [dm-devel] failover does not work with rdac device handler

It is supposed to work. I will look into it and respond.

Can you try one thing

for all your devices, do
        echo rdac > /sys/block/sd?/dh_state

(first you can read the files and see if they all show rdac or not)

and then do your fail over. Let me know what happens.

chandra
On Fri, 2008-10-03 at 18:12 -0600, Moger, Babu wrote:
> Hi,
>
> I have quick question.
>
> I am trying to configure device mapper for my FC array (on my Linux box). I have passed all the arguments from /etc/multipath.conf(like vendor, model etc ..).
>
> Discovery seems fine. But, failover is not working.  I am seeing the following error.
>
> "device-mapper: multipath: Cannot failover device because scsi_dh_rdac was not loaded."
>
> Is it required to add vendor id and model id anywhere else to support this device?
>
> Thanks
> Babu Moger
>
>
> -----Original Message-----
> From: dm-devel-bounces at redhat.com [mailto:dm-devel-bounces at redhat.com] On Behalf Of Moger, Babu
> Sent: Wednesday, October 01, 2008 4:48 PM
> To: device-mapper development; linux-scsi at vger.kernel.org
> Subject: [dm-devel] failover does not work with rdac device handler
>
> Hi All,
>
> I am new to the device mapper and just thought I will set-up device mapper on our arrays. I am using the latest kernel 2.6.27.rc6 and got the latest multipath-tools from upstream.
>
> I updated /etc/multipath.conf with all the information (vendor, product, hardware_handler, prio etc  ...). Note that my device is not part of rdac_dev_list.
>
> Discovery worked fine. "multipath -ll" displays all the information. I can see that it is picking up rdac device handler.
>
> But I found that for some reason failover/failback is not working.  I am seeing following these messages.
>
> "device-mapper: multipath: Cannot failover device because scsi_dh_rdac was not loaded."
>
> I can see that scsi_dh_rdac driver is already loaded.
>
> I did some more investigation. Found that failover works fine if I add vendor, model in rdac_dev_list (in file scsi_dh_rdac.c).
>
> My question - is it required to add all the supported vendor and model names in rdac_dev_list?
>
> Appreciate your responses.
>
> Thanks
> Babu Moger
>
>
>
>
>
>
>
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