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Re: [dm-devel] multipath and StorageWorks HSG80



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 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 dogwood:~$ sudo pvcreate /dev/mapper/red
  Physical volume "/dev/mapper/red" successfully created
sfeehan 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 dogwood:~$
sfeehan dogwood:~$
sfeehan 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 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


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