[Linux-cluster] GFS2 and lvm

[Mario Salcedo]

Thanks. I now understand better GFS2. I probe GFS2 in a cluster of 4
nodes identicals. Maybe for that i dont have problems when I mount
/dev/sdb in all nodes. I think is best using LABEL or CLVM.

2010/2/16 Steven Whitehouse <swhiteho at redhat.com>:
> Hi,
>
> On Mon, 2010-02-15 at 13:33 -0800, Scooter Morris wrote:
>> On 02/15/2010 12:42 PM, Jos Vos wrote:
>> > On Mon, Feb 15, 2010 at 01:20:35PM -0500, Mario Salcedo wrote:
>> >
>> >
>> >> Hi, I am configuring  a Red hat cluster. In the guide say: "A GFS2
>> >> file system must be created on an LVM logical volume that is a linear
>> >> or mirrored volume". Is that true.
>> >>
>> >> I create GFS2 without LVM. I think all ok.
>> >>
>> > Not really...
>> >
>> > How do you ensure then that the device paths of the GFS filesystems
>> > are the same on all nodes (as is required by the shared cluster.conf)?
>> >
>> > A shared disk may appear as /dev/sda in one node, but as /dev/sdb on
>> > another node, for example, dependent on hardware or configuration
>> > details.
>> >
>> >
>> Actually, this is not really true.  We have many GFS2 filesystems on a
>> three node cluster and we don't use LVM.  It really depends on how you
>> are mounting the filesystems.  You really need to mount them by LABEL,
>> so the underlying disk identifiers becomes irrelevant.
>>
>> -- scooter
>>
> Any underlying storage system should be ok provided it provides the
> guarantees required by GFS2 in terms of caching and ordering of
> operations. The reason that the docs mention the use of CLVM is that it
> is a requirement for support, not because other solutions (including
> direct sharing of disks) will not work,
>
> Steve.
>
>
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