[linux-lvm] Multipath / LVM2

[linux-lvm] Multipath / LVM2

[blub]

hello

I have troubles to get multipathing working on gentoo. I have an identical
setup working on a debian box.
The problem is that LVM does not detect labels on the multipath device
node; instead it does try to use a physical path (eg /dev/sda1)

the device nodes /dev/dm-X are not automaticaly created like they get on
debian, I did run dmsetup mknodes which did not create /dev/dm-X nodes, so
i created /dev/dm-0 with the minor/major of the corresponding /dev/mapper/
node. I don't know if this is a problem.

anyway, I've pasted alot of output to http://pastebin.com/wheL4nyE

hope somebody can help me :)

regards

Re: [linux-lvm] Multipath / LVM2

[Luca Berra]

On Tue, Mar 16, 2010 at 05:40:20PM +0100, blub@trans.am wrote:
>hello
>
>I have troubles to get multipathing working on gentoo. I have an identical
>setup working on a debian box.
>The problem is that LVM does not detect labels on the multipath device
>node; instead it does try to use a physical path (eg /dev/sda1)
>
>the device nodes /dev/dm-X are not automaticaly created like they get on
>debian, I did run dmsetup mknodes which did not create /dev/dm-X nodes, so
>i created /dev/dm-0 with the minor/major of the corresponding /dev/mapper/
>node. I don't know if this is a problem.
>
>anyway, I've pasted alot of output to http://pastebin.com/wheL4nyE
>
change the preferred_names in /etc/lvm.conf to reference /dev/mapper
entries before /dev/sd

eg:
preferred_names = [ "^/dev/mapper/" ]

L.


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Re: [linux-lvm] Multipath / LVM2

[malahal]

blub@trans.am [blub@trans.am] wrote:
> hello
> 
> I have troubles to get multipathing working on gentoo. I have an identical
> setup working on a debian box.
> The problem is that LVM does not detect labels on the multipath device
> node; instead it does try to use a physical path (eg /dev/sda1)

One easy way to avoid using the paths rather than actual multipath
devices is to use filtering in /etc/lvm/lvm.conf. Like below:

# Use only names from /dev/mapper directory
filter = [ "a|/dev/mapper/.*|", "r/.*/" ]

> the device nodes /dev/dm-X are not automaticaly created like they get on
> debian, I did run dmsetup mknodes which did not create /dev/dm-X nodes, so
> i created /dev/dm-0 with the minor/major of the corresponding /dev/mapper/
> node. I don't know if this is a problem.

This is odd, maybe something to do with udev rules? Anyway, you don't
need /dev/dm-X nodes if you use LVM filtering.

Re: [linux-lvm] Multipath / LVM2

[blub]

hello
thanks for trying to help :)

I've changed the filter and preferred_names variables to

preferred_names="^/dev/mapper/"
filter=["a|/dev/mapper/.*|", "r/.*/"]

without luck :(

new pvscan output:
http://pastebin.com/5PysR0rD


> On Tue, Mar 16, 2010 at 05:40:20PM +0100, blub@trans.am wrote:
>>hello
>>
>>I have troubles to get multipathing working on gentoo. I have an
>> identical
>>setup working on a debian box.
>>The problem is that LVM does not detect labels on the multipath device
>>node; instead it does try to use a physical path (eg /dev/sda1)
>>
>>the device nodes /dev/dm-X are not automaticaly created like they get on
>>debian, I did run dmsetup mknodes which did not create /dev/dm-X nodes,
>> so
>>i created /dev/dm-0 with the minor/major of the corresponding
>> /dev/mapper/
>>node. I don't know if this is a problem.
>>
>>anyway, I've pasted alot of output to http://pastebin.com/wheL4nyE
>>
> change the preferred_names in /etc/lvm.conf to reference /dev/mapper
> entries before /dev/sd
>
> eg:
> preferred_names = [ "^/dev/mapper/" ]
>
> L.
>
>
> --
> Luca Berra -- bluca@comedia.it
>          Communication Media & Services S.r.l.
>   /"\
>   \ /     ASCII RIBBON CAMPAIGN
>    X        AGAINST HTML MAIL
>   / \
>
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>

Re: [linux-lvm] Multipath / LVM2

[malahal]

Do "rm -rf /etc/lvm/cache" to remove the LVM cache. If you need this at
boot time, of course, you need to create new initramfs with the new
/etc/lvm/lvm.conf file.

blub@trans.am [blub@trans.am] wrote:
> hello
> thanks for trying to help :)
> 
> I've changed the filter and preferred_names variables to
> 
> preferred_names="^/dev/mapper/"
> filter=["a|/dev/mapper/.*|", "r/.*/"]
> 
> without luck :(
> 
> new pvscan output:
> http://pastebin.com/5PysR0rD

I don't see any warnings about any duplicates. What is the problem?

Thanks, Malahal.

Re: [linux-lvm] Multipath / LVM2

[Luca Berra]

On Tue, Mar 16, 2010 at 08:09:16PM +0100, blub@trans.am wrote:
>hello
>thanks for trying to help :)
>
>I've changed the filter and preferred_names variables to
>
>preferred_names="^/dev/mapper/"
>filter=["a|/dev/mapper/.*|", "r/.*/"]
>
>without luck :(

reading your output again i noticed you partitioned the luns on the HDS
(hope at least you aligned the partition)
but i fail to see the partitioned multipath luns in /dev/mapper
rereading again i see a "livecd" prompt
are you by chance using systemrescuecd (gentoo based)? i tried it once and it did not
run kpartix on /dev/mapper.
you should check your udev rules and see why kpartx is not called and
partitions are not created

L.

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Re: [linux-lvm] Multipath / LVM2

[blub]

i could resolve the issue, thanks to all who helped :)
the problem was that there is indeed a partition the the array's and the
partition map was not created. i did use the gentoo live cd, but on an
installed gentoo system the partition maps are not created out-of-the-box
by udev either

anyway, thanks again :)

> On Tue, Mar 16, 2010 at 08:09:16PM +0100, blub@trans.am wrote:
>>hello
>>thanks for trying to help :)
>>
>>I've changed the filter and preferred_names variables to
>>
>>preferred_names="^/dev/mapper/"
>>filter=["a|/dev/mapper/.*|", "r/.*/"]
>>
>>without luck :(
>
> reading your output again i noticed you partitioned the luns on the HDS
> (hope at least you aligned the partition)
> but i fail to see the partitioned multipath luns in /dev/mapper
> rereading again i see a "livecd" prompt
> are you by chance using systemrescuecd (gentoo based)? i tried it once and
> it did not
> run kpartix on /dev/mapper.
> you should check your udev rules and see why kpartx is not called and
> partitions are not created
>
> L.
>
> --
> Luca Berra -- bluca@comedia.it
>          Communication Media & Services S.r.l.
>   /"\
>   \ /     ASCII RIBBON CAMPAIGN
>    X        AGAINST HTML MAIL
>   / \
>
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>