[dm-devel] multipath and StorageWorks HSG80

[Steve Feehan]

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

-- 
Steve Feehan