So in the linux cluster, there is no concept about odd number coordinate disks, which is used to deal with this issue?
anyway, probably I have to use power fencing.
cheers
Yu
On Mon, Jun 15, 2009 at 1:36 PM, Ryan O'Hara <rohara@xxxxxxxxxx> wrote:
On Sun, Jun 14, 2009 at 11:21:08AM +1000, yu song wrote:In a 2 node cluster, fencing becomes a race -- the node fences the
> Hi,
>
> I am planning to build a 2 nodes cluster on rhcl 5.3, and looking for what
> fencing method I could use.
>
> On the storage side, it is EMC clarion and supports scsi 3 reservation.
>
> So I'm thinking to use fence_scsi agent to do the disk fencing. however,
> according the redhat website, it states that fence_scsi does not support
> two nodes cluster.
>
> Could anyone kindly explain it why? (never had this issue when use veritas
> cluster)
other node first wins. This works well with power fencing, but not so
well with SAN fencing (eg. fence_scsi).
The problem with fence_scsi in a 2 node cluster is this:
Suppose we have 2 node, call them A and B. Also assume we have multple
LUNs, which we will call lun1, lun2, lun3. Consider what happens when
a network partition occurs -- both nodes attempt to fence one
another. It is possible that A could remove B's key from lun1 and
lun2, but node B could remove node A's key from lun3. This is
inconsistent and there is no clear "winner".
Ryan
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