Re: RE: Dell MD3000i issues with dm mp

[Mike Christie <michaelc@cs.wisc.edu>]

Moger, Babu wrote:
> I don’t see any apparent reason for these messages(“rdac Dettached”) by looking at the log. There are some issci session failure messages.  I don’t understand those messages very well.  You may have to ask some iscsi experts to look at it.
> 

The http://pastebin.com/d97ae1ad link does not work anymore. If you 
could put the log back up, I can look at the iscsi messages.


> ________________________________
> From: dm-devel-bounces@redhat.com [mailto:dm-devel-bounces@redhat.com] On Behalf Of Kurt Bechstein
> Sent: Tuesday, April 14, 2009 12:44 PM
> To: device-mapper development
> Subject: [dm-devel] RE: Dell MD3000i issues with dm mp
> 
> No devices were detached during this sequence at least not physically anyways.
> 
> From: dm-devel-bounces@redhat.com [mailto:dm-devel-bounces@redhat.com] On Behalf Of Moger, Babu
> Sent: Tuesday, April 14, 2009 1:38 PM
> To: device-mapper development
> Subject: [dm-devel] RE: Dell MD3000i issues with dm mp
> 
> I am seeing few “rdac Dettached” messages. There are only messages I am bit concerned about (unless you disconnected some devices purposefully during the test). I am not concerned about other messages.
> 
> Thanks
> Babu Moger
> ________________________________
> From: dm-devel-bounces@redhat.com [mailto:dm-devel-bounces@redhat.com] On Behalf Of Kurt Bechstein
> Sent: Tuesday, April 14, 2009 12:10 PM
> To: device-mapper development
> Subject: [dm-devel] RE: Dell MD3000i issues with dm mp
> 
> Here is a snippet of my /var/log/messages from this morning’s boot sequence after iscsi started and some of the output I’m seeing.  Seems like quite a bit to me.
> 
> http://pastebin.com/d97ae1ad
> 
> From: dm-devel-bounces@redhat.com [mailto:dm-devel-bounces@redhat.com] On Behalf Of Moger, Babu
> Sent: Tuesday, April 14, 2009 12:12 PM
> To: device-mapper development
> Subject: [dm-devel] RE: Dell MD3000i issues with dm mp
> 
> I would think it should be pretty sparse.
> 
> Thanks
> Babu Moger
> ________________________________
> From: dm-devel-bounces@redhat.com [mailto:dm-devel-bounces@redhat.com] On Behalf Of Kurt Bechstein
> Sent: Tuesday, April 14, 2009 10:57 AM
> To: device-mapper development
> Subject: [dm-devel] RE: Dell MD3000i issues with dm mp
> 
> I actually tried doing that by doing a mkinitrd /boot/initrdfile –preload=scsi_dh_rdac kernelversion and booted using the initrd and it still seemed to crank out quite a few errors.  With doing it this way, should I still expect to see a good deal of I/O errors or should they pretty sparse?
> 
> From: dm-devel-bounces@redhat.com [mailto:dm-devel-bounces@redhat.com] On Behalf Of Moger, Babu
> Sent: Tuesday, April 14, 2009 11:38 AM
> To: device-mapper development
> Subject: [dm-devel] RE: Dell MD3000i issues with dm mp
> 
> Yes, this could happen during the boot where the scsi_dh_rdac handler is not yet loaded. You might want to try adding scsi_dh_rdac in the initrd.  This will help to cut short all your error messages. I don’t see any problem with your multipath.conf.
> 
> Thanks
> Babu Moger
> ________________________________
> From: dm-devel-bounces@redhat.com [mailto:dm-devel-bounces@redhat.com] On Behalf Of Kurt Bechstein
> Sent: Tuesday, April 14, 2009 9:54 AM
> To: dm-devel@redhat.com
> Subject: [dm-devel] Dell MD3000i issues with dm mp
> 
> Greetings everyone, I have a RHEL 5.3 host attached to two Dell MD3000i storage arrays via iscsi.  I’m having some interesting issues upon bootup in this setup.  Between the two arrays I’m accessing 24 luns so after my iscsi service kicks in I get tons and tons of I/O error messages going across the screen.  This can go on for 15-20 minutes or longer.  It would appear that some I/O is being sent to the passive paths and they are returning errors.  It would seem the scsi layer is doing its thing to scan for partitions and probably causing the I/O that is being seen.  Is there any way to suppress/avoid this scenario?  Also, I thought I would post my multipath.conf file just to have some other eyes have a look at it and make sure I’m not missing something obvious so that is below.  Thanks in advance!
> 
> 
> devices {
>         device {
>                vendor                  "DELL"
>                product                 "MD3000i"
>                features                 "0"
>                getuid_callout          "/sbin/scsi_id -g -u -s /block/%n"
>                prio_callout            "/sbin/mpath_prio_rdac /dev/%n"
>                hardware_handler        "1 rdac"
>                path_grouping_policy    group_by_prio
>                failback                immediate
>                path_checker            rdac
>                prio                     "rdac"
> 
>        }
> }
> multipaths {
>         mulitpath {
>                 device {
>                         vendor DELL
>                         product MD3000i
>                 }
>         }
> }
> 
> 
> 
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