grow MULTIPATH RAID

grow MULTIPATH RAID

am 25.03.2011 04:13:41 von Shamim

Hello Experts,

Please help me to grow MULTIPATH RAID. =20
My problem:
I've Linux box which have MULTIPATH RAID created on them. Now we need t=
o remove
those old LUN and move data onto new LUN presented to those boxes.

My initially thought was to grow the current MULTIPATH RAID (/dev/md0)=
and=20
make old LUN as spare and then failed and then remove(Is this a right
approach?). When Iâ€=99m try adding new LUNs to it, they are getti=
ng added as spare
( as shown below). And when I try to grow , it refuse to do so. Below=
are the
steps that I performed and error message.(Cannot reshaped!!)=20
( I read somehwere that we canâ€=99t grow MULTIPATH RAID, if it is=
TRUE, then what
would be suggested solution to move data from old LUNs to new LUNs)
Please help
--------------------------------------------------
=20
# mdadm --detail /dev/md0
/dev/md0:
Version : 0.90
Creation Time : Thu Mar 24 13:54:41 2011
Raid Level : multipath
Array Size : 10486016 (10.00 GiB 10.74 GB)
Raid Devices : 2
Total Devices : 4
Preferred Minor : 0
Persistence : Superblock is persistent

Update Time : Thu Mar 24 13:54:41 2011
State : clean
Active Devices : 2
Working Devices : 4
Failed Devices : 0
Spare Devices : 2

UUID : xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Events : 0.3

Number Major Minor RaidDevice State
0 65 0 0 active sync /dev/sdq
1 8 96 1 active sync /dev/sdg
------------------------------------------------------------ --------
# mdadm /dev/md0 --add /dev/sdr /dev/sdh
mdadm: added /dev/sdr
mdadm: re-added /dev/sdh

------------------------------------------------------------ --------
# mdadm --detail /dev/md0
/dev/md0:
Version : 0.90
Creation Time : Thu Mar 24 13:54:41 2011
Raid Level : multipath
Array Size : 10486016 (10.00 GiB 10.74 GB)
Raid Devices : 2
Total Devices : 4
Preferred Minor : 0
Persistence : Superblock is persistent

Update Time : Thu Mar 24 13:54:41 2011
State : clean
Active Devices : 2
Working Devices : 4
Failed Devices : 0
Spare Devices : 2

UUID : xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Events : 0.3

Number Major Minor RaidDevice State
0 65 0 0 active sync /dev/sdq
1 8 96 1 active sync /dev/sdg

2 65 16 - spare /dev/sdr
3 8 112 - spare /dev/sdh

------------------------------------------------------------ --------
# mdadm --grow /dev/md0 --raid-disks=3D4
mdadm: multipath array /dev/md0 cannot be reshaped.



--
To unsubscribe from this list: send the line "unsubscribe linux-raid" i=
n
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html

Re: grow MULTIPATH RAID

am 25.03.2011 06:29:16 von NeilBrown

On Fri, 25 Mar 2011 03:13:41 +0000 (UTC) shamim w=
rote:

> Hello Experts,
>=20
> Please help me to grow MULTIPATH RAID. =20
> My problem:
> I've Linux box which have MULTIPATH RAID created on them. Now we need=
to remove
> those old LUN and move data onto new LUN presented to those boxes.
>=20
> My initially thought was to grow the current MULTIPATH RAID (/dev/md=
0) and=20
> make old LUN as spare and then failed and then remove(Is this a righ=
t
> approach?). When Iâ€=99m try adding new LUNs to it, they are get=
ting added as spare
> ( as shown below). And when I try to grow , it refuse to do so. Bel=
ow are the
> steps that I performed and error message.(Cannot reshaped!!)=20
> ( I read somehwere that we canâ€=99t grow MULTIPATH RAID, if it =
is TRUE, then what
> would be suggested solution to move data from old LUNs to new LUNs)
> Please help

No, you cannot grow an md/multipath device.
However you can simply create a new multipath config across
the set of paths that you want to use.

mdadm --stop /dev/md0
mdadm --create /dev/md0 --l multipath -n 4 ..list..of..paths...

However I recommend that you stop using md/multipath and look in to
using dm-multipath instead. See the 'multipath' command.

dm-multipath is actively developed. md/multipath is not.

NeilBrown


> --------------------------------------------------
> =20
> # mdadm --detail /dev/md0
> /dev/md0:
> Version : 0.90
> Creation Time : Thu Mar 24 13:54:41 2011
> Raid Level : multipath
> Array Size : 10486016 (10.00 GiB 10.74 GB)
> Raid Devices : 2
> Total Devices : 4
> Preferred Minor : 0
> Persistence : Superblock is persistent
>=20
> Update Time : Thu Mar 24 13:54:41 2011
> State : clean
> Active Devices : 2
> Working Devices : 4
> Failed Devices : 0
> Spare Devices : 2
>=20
> UUID : xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> Events : 0.3
>=20
> Number Major Minor RaidDevice State
> 0 65 0 0 active sync /dev/sdq
> 1 8 96 1 active sync /dev/sdg
> ------------------------------------------------------------ --------
> # mdadm /dev/md0 --add /dev/sdr /dev/sdh
> mdadm: added /dev/sdr
> mdadm: re-added /dev/sdh
>=20
> ------------------------------------------------------------ --------
> # mdadm --detail /dev/md0
> /dev/md0:
> Version : 0.90
> Creation Time : Thu Mar 24 13:54:41 2011
> Raid Level : multipath
> Array Size : 10486016 (10.00 GiB 10.74 GB)
> Raid Devices : 2
> Total Devices : 4
> Preferred Minor : 0
> Persistence : Superblock is persistent
>=20
> Update Time : Thu Mar 24 13:54:41 2011
> State : clean
> Active Devices : 2
> Working Devices : 4
> Failed Devices : 0
> Spare Devices : 2
>=20
> UUID : xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> Events : 0.3
>=20
> Number Major Minor RaidDevice State
> 0 65 0 0 active sync /dev/sdq
> 1 8 96 1 active sync /dev/sdg
>=20
> 2 65 16 - spare /dev/sdr
> 3 8 112 - spare /dev/sdh
>=20
> ------------------------------------------------------------ --------
> # mdadm --grow /dev/md0 --raid-disks=3D4
> mdadm: multipath array /dev/md0 cannot be reshaped.
>=20
>=20
>=20
> --
> To unsubscribe from this list: send the line "unsubscribe linux-raid"=
in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html

--
To unsubscribe from this list: send the line "unsubscribe linux-raid" i=
n
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html

Re: grow MULTIPATH RAID

am 25.03.2011 07:06:48 von Roberto Spadim

hum, what diference about dmraid and mdraid? dm and md what's the
diference? (md=3D multiple devices?! dm=3D? )

2011/3/25 NeilBrown :
> On Fri, 25 Mar 2011 03:13:41 +0000 (UTC) shamim =
wrote:
>
>> Hello Experts,
>>
>> Please help me to grow MULTIPATH RAID.
>> My problem:
>> I've Linux box which have MULTIPATH RAID created on them. Now we nee=
d to remove
>> those old LUN and move data onto new LUN presented to those boxes.
>>
>> My initially thought was to grow the =A0current MULTIPATH RAID (/dev=
/md0) and
>> make old LUN as spare and then =A0failed and then remove(Is this a r=
ight
>> approach?). =A0When I=92m try adding new LUNs to it, they are gettin=
g added as spare
>> ( as shown below). =A0And when I try to grow , it refuse to do so. =A0=
Below are the
>> steps that I performed and error message.(Cannot reshaped!!)
>> ( I read somehwere =A0that we can=92t grow MULTIPATH RAID, if it is =
TRUE, then what
>> would be suggested solution to move data from old LUNs to new LUNs)
>> Please help
>
> No, you cannot grow an md/multipath device.
> However you can simply create a new multipath config across
> the set of paths that you want to use.
>
> mdadm --stop /dev/md0
> mdadm --create /dev/md0 --l multipath -n 4 ..list..of..paths...
>
> However I recommend that you stop using md/multipath and look in to
> using dm-multipath instead. =A0See the 'multipath' command.
>
> dm-multipath is actively developed. =A0md/multipath is not.
>
> NeilBrown
>
>
>> --------------------------------------------------
>>
>> # mdadm --detail /dev/md0
>> /dev/md0:
>> =A0 =A0 =A0 =A0 Version : 0.90
>> =A0 Creation Time : Thu Mar 24 13:54:41 2011
>> =A0 =A0 =A0Raid Level : multipath
>> =A0 =A0 =A0Array Size : 10486016 (10.00 GiB 10.74 GB)
>> =A0 =A0Raid Devices : 2
>> =A0 Total Devices : 4
>> Preferred Minor : 0
>> =A0 =A0 Persistence : Superblock is persistent
>>
>> =A0 =A0 Update Time : Thu Mar 24 13:54:41 2011
>> =A0 =A0 =A0 =A0 =A0 State : clean
>> =A0Active Devices : 2
>> Working Devices : 4
>> =A0Failed Devices : 0
>> =A0 Spare Devices : 2
>>
>> =A0 =A0 =A0 =A0 =A0 =A0UUID : xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>> =A0 =A0 =A0 =A0 =A0Events : 0.3
>>
>> =A0 =A0 Number =A0 Major =A0 Minor =A0 RaidDevice State
>> =A0 =A0 =A0 =A00 =A0 =A0 =A065 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A00 =A0=
=A0 =A0active sync =A0 /dev/sdq
>> =A0 =A0 =A0 =A01 =A0 =A0 =A0 8 =A0 =A0 =A0 96 =A0 =A0 =A0 =A01 =A0 =A0=
=A0active sync =A0 /dev/sdg
>> ------------------------------------------------------------ --------
>> # mdadm /dev/md0 --add /dev/sdr /dev/sdh
>> mdadm: added /dev/sdr
>> mdadm: re-added /dev/sdh
>>
>> ------------------------------------------------------------ --------
>> # mdadm --detail /dev/md0
>> /dev/md0:
>> =A0 =A0 =A0 =A0 Version : 0.90
>> =A0 Creation Time : Thu Mar 24 13:54:41 2011
>> =A0 =A0 =A0Raid Level : multipath
>> =A0 =A0 =A0Array Size : 10486016 (10.00 GiB 10.74 GB)
>> =A0 =A0Raid Devices : 2
>> =A0 Total Devices : 4
>> Preferred Minor : 0
>> =A0 =A0 Persistence : Superblock is persistent
>>
>> =A0 =A0 Update Time : Thu Mar 24 13:54:41 2011
>> =A0 =A0 =A0 =A0 =A0 State : clean
>> =A0Active Devices : 2
>> Working Devices : 4
>> =A0Failed Devices : 0
>> =A0 Spare Devices : 2
>>
>> =A0 =A0 =A0 =A0 =A0 =A0UUID : xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>> =A0 =A0 =A0 =A0 =A0Events : 0.3
>>
>> =A0 =A0 Number =A0 Major =A0 Minor =A0 RaidDevice State
>> =A0 =A0 =A0 =A00 =A0 =A0 =A065 =A0 =A0 =A0 =A00 =A0 =A0 =A0 =A00 =A0=
=A0 =A0active sync =A0 /dev/sdq
>> =A0 =A0 =A0 =A01 =A0 =A0 =A0 8 =A0 =A0 =A0 96 =A0 =A0 =A0 =A01 =A0 =A0=
=A0active sync =A0 /dev/sdg
>>
>> =A0 =A0 =A0 =A02 =A0 =A0 =A065 =A0 =A0 =A0 16 =A0 =A0 =A0 =A0- =A0 =A0=
=A0spare =A0 /dev/sdr
>> =A0 =A0 =A0 =A03 =A0 =A0 =A0 8 =A0 =A0 =A0112 =A0 =A0 =A0 =A0- =A0 =A0=
=A0spare =A0 /dev/sdh
>>
>> ------------------------------------------------------------ --------
>> # mdadm --grow /dev/md0 --raid-disks=3D4
>> mdadm: multipath array /dev/md0 cannot be reshaped.
>>
>>
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-raid=
" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at =A0http://vger.kernel.org/majordomo-info.html
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-raid"=
in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at =A0http://vger.kernel.org/majordomo-info.html
>



--=20
Roberto Spadim
Spadim Technology / SPAEmpresarial
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" i=
n
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html

Re: grow MULTIPATH RAID

am 25.03.2011 07:21:14 von NeilBrown

On Fri, 25 Mar 2011 03:06:48 -0300 Roberto Spadim
wrote:

> hum, what diference about dmraid and mdraid? dm and md what's the
> diference? (md= multiple devices?! dm=? )

Completely different sets of code.
dm = Device Mapper.

NeilBrown
--
To unsubscribe from this list: send the line "unsubscribe linux-raid" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html