Hi. We have Bladecenter H with HS22 servers inside. All servers have
0b:00.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1064ET
PCI-Express Fusion-MPT SAS (rev 10)
with two possible external SAS connections which we use to connect them
with DS3512 (IBM datastorage) using two SAS cables and thus multipath
configuration is in place. We use ubuntu 10.04 here and since in-stock
scsi_dh_rdac kernel module does not support IBM 1746 devices I've
patched it and rebuild kernel. Now, as I modproble module I see the
following in dmesg:

[ 27.861388] sd 0:0:2:1: rdac: LUN 1 (owned)
[ 27.861836] sd 0:0:3:1: rdac: LUN 1 (unowned)
[ 27.861840] rdac: device handler registered

That's Ok, but multipath output does not have rdac:

root@btv1:~# multipath -l
vod (360080e50001baa46000025834d501798) dm-0 IBM ,1746 FASt
[size=13T][features=0][hwhandler=0]
\_ round-robin 0 [prio=0][active]
\_ 0:0:2:1 sdc 8:32 [active][undef]
\_ round-robin 0 [prio=0][enabled]
\_ 0:0:3:1 sdd 8:48 [active][undef]


Is this normal? On Gentoo system connected to the same DS I see:

mon1 ~ # multipath -l
vod (360080e50001baa46000025834d501798) dm-0 IBM,1746 FAStT
size=13T features='3 queue_if_no_path pg_init_retries 50' hwhandler='1
rdac' wp=rw
|-+- policy='round-robin 0' prio=-1 status=active
| `- 0:0:2:1 sdc 8:32 active undef running
`-+- policy='round-robin 0' prio=-1 status=enabled
`- 0:0:3:1 sdd 8:48 active undef running

Could you tell me what's hwhandler and why it's 0 in one case and 1 in
another.

Many thanks for any explanations in advance,
--
Peter.

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Hi. We have Bladecenter H with HS22 servers inside. All servers have
0b:00.0 SCSI storage controller: LSI Logic / Symbios Logic SAS1064ET
PCI-Express Fusion-MPT SAS (rev 10)
with two possible external SAS connections which we use to connect them
with DS3512 (IBM datastorage) using two SAS cables and thus multipath
configuration is in place. We use ubuntu 10.04 here and since in-stock
scsi_dh_rdac kernel module does not support IBM 1746 devices I've
patched it and rebuild kernel. Now, as I modproble module I see the
following in dmesg:

[ 27.861388] sd 0:0:2:1: rdac: LUN 1 (owned)
[ 27.861836] sd 0:0:3:1: rdac: LUN 1 (unowned)
[ 27.861840] rdac: device handler registered

That's Ok, but multipath output does not have rdac:

root@btv1:~# multipath -l
vod (360080e50001baa46000025834d501798) dm-0 IBM ,1746 FASt
[size=13T][features=0][hwhandler=0]
\_ round-robin 0 [prio=0][active]
\_ 0:0:2:1 sdc 8:32 [active][undef]
\_ round-robin 0 [prio=0][enabled]
\_ 0:0:3:1 sdd 8:48 [active][undef]


Is this normal? On Gentoo system connected to the same DS I see:

mon1 ~ # multipath -l
vod (360080e50001baa46000025834d501798) dm-0 IBM,1746 FAStT
size=13T features='3 queue_if_no_path pg_init_retries 50' hwhandler='1
rdac' wp=rw
|-+- policy='round-robin 0' prio=-1 status=active
| `- 0:0:2:1 sdc 8:32 active undef running
`-+- policy='round-robin 0' prio=-1 status=enabled
`- 0:0:3:1 sdd 8:48 active undef running

Could you tell me what's hwhandler and why it's 0 in one case and 1 in
another.

Many thanks for any explanations in advance,
--
Peter.

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Thank you for detailed answer Christophe.

В Срд, 09/02/2011 в 10:49 +0100, Christophe Varoqui пишет:
> On your ubuntu setup, multipath tools picked the default hardware
> handler (none, ie 0) whereas on your gentoo setup the hardware handler
> is explicitely set for use with your storage device.
>
> Now 2 choices :
> 1/ upgrade multipath-tools
> or
> 2/ set up your device definition in multipath.conf to override internal
> defaults

I'll try to upgrade multipath-tools, but as for second choice it looks
like following configuration should work:

root@btv1:~# cat /etc/multipath.conf
defaults {
path_checker rdac
}

blacklist {
devnode "^sd[a-b]"
}

multipaths {
multipath {
wwid 360080e50001baa46000025834d501798
alias vod
path_checker rdac
}
}

I even think that rdac definition in inside multipath is redundant but
if I remove it nothing changes. And looking at verbose output it looks
like it reads configfile (at least sda and sdb devices are blacklisted
and it tells that I have rdac defined in configfile).

root@btv1:~# multipath -v3 -ll
ram0: device node name blacklisted
[...snip...]
ram15: device node name blacklisted
loop0: device node name blacklisted
[...snip...]
loop7: device node name blacklisted
sda: device node name blacklisted
sdb: device node name blacklisted
sdc: not found in pathvec
sdc: mask = 0x5
sdc: dev_t = 8:32
sdc: size = 27341848576
sdc: subsystem = scsi
sdc: vendor = IBM
sdc: product = 1746 FAStT
sdc: rev = 1070
sdc: h:b:t:l = 0:0:2:1
sdd: not found in pathvec
sdd: mask = 0x5
sdd: dev_t = 8:48
sdd: size = 27341848576
sdd: subsystem = scsi
sdd: vendor = IBM
sdd: product = 1746 FAStT
sdd: rev = 1070
sdd: h:b:t:l = 0:0:3:1
md0: device node name blacklisted
dm-0: device node name blacklisted
===== paths list =====
uuid hcil dev dev_t pri dm_st chk_st vend/prod/rev
0:0:2:1 sdc 8:32 -1 [undef][undef] IBM ,1746 FAStT
0:0:3:1 sdd 8:48 -1 [undef][undef] IBM ,1746 FAStT
params = 0 0 2 1 round-robin 0 1 1 8:32 1000 round-robin 0 1 1 8:48
1000
status = 2 0 0 0 2 1 A 0 1 0 8:32 A 0 E 0 1 0 8:48 A 0
sdc: mask = 0x4
sdc: path checker = rdac (config file default)
sdc: state = 2
sdc: mask = 0x8
sdc: getprio = NULL (internal default)
sdc: prio = 1
sdd: mask = 0x4
sdd: path checker = rdac (config file default)
sdd: state = 4
sdd: mask = 0x8
sdd: getprio = NULL (internal default)
sdd: prio = 1
vod (360080e50001baa46000025834d501798) dm-0 IBM ,1746 FASt
[size=13T][features=0][hwhandler=0]
\_ round-robin 0 [prio=1][active]
\_ 0:0:2:1 sdc 8:32 [active][ready]
\_ round-robin 0 [prio=1][enabled]
\_ 0:0:3:1 sdd 8:48 [active][ghost]


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Peter Volkov [peter.volkov@gmail.com] wrote:
> Thank you for detailed answer Christophe.
>
> В Срд, 09/02/2011 в 10:49 +0100, Christophe Varoqui пишет:
> > On your ubuntu setup, multipath tools picked the default hardware
> > handler (none, ie 0) whereas on your gentoo setup the hardware handler
> > is explicitely set for use with your storage device.
> >
> > Now 2 choices :
> > 1/ upgrade multipath-tools
> > or
> > 2/ set up your device definition in multipath.conf to override internal
> > defaults
>
> I'll try to upgrade multipath-tools, but as for second choice it looks
> like following configuration should work:
>
> root@btv1:~# cat /etc/multipath.conf
> defaults {
> path_checker rdac
> }

Checker name is in the controller section and that default may
overwrite the above. BTW, checker name is different from
hardware handler.

>
> blacklist {
> devnode "^sd[a-b]"
> }
>
> multipaths {
> multipath {
> wwid 360080e50001baa46000025834d501798
> alias vod
> path_checker rdac

The above should work for path checker but path checker is different
from hardware handler.

Thanks, Malahal.

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