From mboxrd@z Thu Jan  1 00:00:00 1970
From: Bernd Schubert <bs@q-leap.de>
Subject: Re: Reopen: 16 HDDs too much for RAID6?
Date: Fri, 28 Mar 2008 12:20:09 +0100
Message-ID: <200803281220.09419.bs@q-leap.de>
References: <20080306100128.8daad6bd.taeuber@bbaw.de> <200803281135.20890.bs@q-leap.de> <20080328115537.ad40f3dc.taeuber@bbaw.de>
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To: Lars =?iso-8859-1?q?T=E4uber?= <taeuber@bbaw.de>
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On Friday 28 March 2008 11:55:37 Lars T=E4uber wrote:
> Hi Bernd,
>
> Bernd Schubert <bs@q-leap.de> schrieb:
> > > Here the conf file:
> > > monosan:~ # cat /etc/mdadm.conf
> > > DEVICE /dev/sd[ab][0-9] /dev/dm-*
> > > ARRAY /dev/md2 level=3Draid1 UUID=3Dd9d31de2:e6dbd3c3:37c7ea09:88=
2a64e5
> > > ARRAY /dev/md3 level=3Draid1 num-devices=3D2
> > > UUID=3Da8687183:a79e514c:ca492c4b:ffd4384f ARRAY /dev/md4 level=3D=
raid6
> > > num-devices=3D15 spares=3D1 UUID=3Dcfcbe071:f6766d8f:0f1ffefa:892=
d09c3 ARRAY
> > > /dev/md9 level=3Draid1 num-devices=3D2 name=3D9
> > > UUID=3Ddb687150:614e76fd:28feefc0:b1aae572
> > >
> > > All dm-* devices are really distinctive. I could post the
> > > /etc/multipath.conf too if you want.
>
> here is the file:
> monosan:~ # cat /etc/multipath.conf
> #
> # This configuration file is generated by Yast, do not modify it
> # manually please.
> #
> defaults {
>         polling_interval        "0"
>         user_friendly_names     "yes"
> #       path_grouping_policy    "multibus"
> }
>
> blacklist {
> #       devnode "*"
>         wwid "SATA_WDC_WD1600YS-01_WD-WCAP02964085"
>         wwid "SATA_WDC_WD1600YS-01_WD-WCAP02965435"
> }

Hmm, maybe you are creating multipath of multipath?

Here's something from a config of our systems:

devnode_blacklist {
        devnode "^(ram|raw|loop|fd|md|dm-|sr|scd|st)[0-9]*"
}



>
> blacklist_exceptions {
> }
>
> multipaths {
>         mutlipath {
>                 wwid "SATA_ST31000340NS_5QJ02TBK"
>         }

I would set user friendly names using the alias paramter, something lik=
e this

multipaths {
        multipath {
                wwid                    360050cc000203ffc00000000000000=
19
                alias                   raid1a-ost
        }

> I only have very little experience with multipathing, but please send
> > your config. The fact you really do use multipathing only confirms =
my
> > initial guess it is a multipath and not a md problem.
>
> But when I assemble the array after a clean shutdown after it has bee=
n
> initially synced there is no problem. Just if the array was degraded =
it has
> such duplicated superblocks. How comes?

No idea so far, but please do some blacklisting. And if you will set mo=
re=20
readable names like "/dev/disk8" instead of "dm-8", it might get much m=
ore=20
easy to figure out what it wrong.

Cheers,
Bernd

--=20
Bernd Schubert
Q-Leap Networks GmbH
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