[dm-devel] multipath and StorageWorks HSG80

[Christophe Varoqui]

Steve Feehan a écrit :
> Hello. I'm trying to figure out multipath on a StorageWorks HSG80
> contoller. I'm using Ubuntu "Dapper" with the following software
> versions:
>
>   kernel:           2.6.15-20-server
>   multipath-tools:  0.4.7-1ubuntu4
>
> >From what I've been reading[1], I gather that I need to use the
> dm-hp-sw kernel module. So I applied the patches[2,3,4,5] to
> the kernel and setup the /etc/multipath.conf as follows:
>
> devices {
>
>         device {
>                 vendor                  "DEC"
>                 product                 "HSG80"
>                 path_grouping_policy    group_by_serial
>                 path_checker            hp_sw
>                 features                "1 queue_if_no_path"
>                 hardware_handler        "1 hp_sw"
>         }
> }
>
> multipaths {
>         multipath {
>                 wwid    60001fe10015bf500009947159810015
>                 alias   red
>         }
> }
>
> >From what I can tell, it is basically working:
>
> sfeehan at dogwood:~$ sudo multipath -ll
> red (360001fe10015bf500009947159810015)
> [size=203 GB][features=1 queue_if_no_path][hwhandler=1 hp_sw]
> \_ round-robin 0 [prio=2][active]
>  \_ 0:0:0:1 sda 8:0   [active][ready]
>  \_ 0:0:1:1 sdb 8:16  [active][ready]
> \_ round-robin 0 [prio=2][enabled]
>  \_ 0:0:2:1 sdc 8:32  [active][ghost]
>  \_ 0:0:3:1 sdd 8:48  [active][ghost]
>
>
> And now the problem: I see quite a few errors in dmesg:
>
>
> [42949392.230000] sd 0:0:2:1: Device not ready.
> [42949392.230000] end_request: I/O error, dev sdc, sector 426583424
> [42949392.230000] printk: 515 messages suppressed.
> [42949392.230000] Buffer I/O error on device sdc, logical block
> 213291712
> [42949392.230000] sd 0:0:2:1: Device not ready.
> [42949392.230000] end_request: I/O error, dev sdc, sector 426583424
> [42949392.230000] sd 0:0:3:1: Device not ready.
> [42949392.230000] end_request: I/O error, dev sdd, sector 426583424
> [42949392.230000] sd 0:0:3:1: Device not ready.
> [42949392.230000] end_request: I/O error, dev sdd, sector 426583424
>
>
> And when I put LVM on top of the multipath device I get lots
> of errors:
>
> sfeehan at dogwood:~$ sudo pvcreate /dev/mapper/red
>   Physical volume "/dev/mapper/red" successfully created
> sfeehan at dogwood:~$ sudo vgcreate vg0 /dev/mapper/red
>   Found duplicate PV qDhK4gPTGtzXAm7jPQf0uf07a0FQs2qL: using /dev/sdb1
> not /dev/sda1
>   /dev/sdc: read failed after 0 of 2048 at 0: Input/output error
>   /dev/sdd: read failed after 0 of 2048 at 0: Input/output error
>   Found duplicate PV qDhK4gPTGtzXAm7jPQf0uf07a0FQs2qL: using /dev/sda1
> not /dev/sdb1
>   Found duplicate PV qDhK4gPTGtzXAm7jPQf0uf07a0FQs2qL: using /dev/sdb1
> not /dev/sda1
>   /dev/sdc: read failed after 0 of 1024 at 0: Input/output error
>   /dev/sdc: read failed after 0 of 2048 at 0: Input/output error
>   /dev/sdd: read failed after 0 of 1024 at 0: Input/output error
>   /dev/sdd: read failed after 0 of 2048 at 0: Input/output error
>   Volume group "vg0" successfully created
> sfeehan at dogwood:~$
> sfeehan at dogwood:~$
> sfeehan at dogwood:~$ sudo lvcreate -L 10G -n test vg0
>   Found duplicate PV qDhK4gPTGtzXAm7jPQf0uf07a0FQs2qL: using /dev/sdb1
> not /dev/sda1
>   /dev/sdc: read failed after 0 of 2048 at 0: Input/output error
>   /dev/sdd: read failed after 0 of 2048 at 0: Input/output error
>   Logical volume "test" created
> sfeehan at dogwood:~$
>
>
> So... what are the errors about? Are they significant? What
> if anything can I do to resolve them?
>
> Thanks.
>
> Steve
>
>
> [1] [dm-devel] StorageWorks multipath support
>     http://www.redhat.com/archives/dm-devel/2005-June/msg00105.html
>
> [2] [dm-devel] [PATCH RFT/RFC 1/4] export block layer helpers
>     http://www.redhat.com/archives/dm-devel/2005-September/msg00097.html
>
> [3] [dm-devel] [PATCH RFT/RFC 2/4] add dm_scsi helpers
>     http://www.redhat.com/archives/dm-devel/2005-September/msg00098.html
>
> [4] [dm-devel] [PATCH RFT/RFC 3/4] convert dm emc
>     http://www.redhat.com/archives/dm-devel/2005-September/msg00099.html
>
> [5] [dm-devel] [PATCH RFT/RFC 4/4] add dm-hp-sw hw handler
>     http://www.redhat.com/archives/dm-devel/2005-September/msg00100.html
>
>   
Overall, that's very good howto material, if you care to feed the wiki.

The IO errors are due to lvm tools trying to scan the individual paths, 
including those not usable, where they should only care about the 
multipath devices.

You should blacklist the individual path in the lvm config.


Regards,
cvaroqui