[Ocfs2-users] Another node is heartbeating in our slot

[Werner van der Walt]

Okay so we are in agreement then as per your second point that its multiple
nodes with a single shared block device :)

I am still unclear on your first point though...
Scenario is as follows:
- 2 x iSCSI hosts both exporting an iSCSI block device each (let's call it
host1 and host2). The block devices are locally attached storage to each of
the hosts so they are different block devices.
- 2 x nodes attempting connection to both the iSCSI hosts at the same time.
Setting both iSCSI connections up for each node is no problem as I just do a
discovery per node for the two iSCSI targets and it gets added locally
(let's say /dev/sdb and /dev/sdc).
- I now need to set up OCFS2 for each of /dev/sdb and /dev/sdc to format the
file systems and mount.
- Configuring /etc/ocfs2/cluster.conf it only allows me to set up one
cluster so I will point that to host1 on each of the nodes by giving it a
cluster name of host1 and node numbers of 0 and 1 respectively.

Now my problem is how do I create the OCFS2 cluster config file for host2
and give it node numbers 0 and 1 again for the shared file system on host2?
According to the docs I cannot do this in /etc/ocfs2/cluster.conf again a
second time even if the cluster name details are different?

Werner

-----Original Message-----
From: Sunil Mushran [mailto:Sunil.Mushran at oracle.com] 
Sent: Tuesday, January 08, 2008 8:12 PM
To: Werner van der Walt
Cc: ocfs2-users at oss.oracle.com
Subject: Re: [Ocfs2-users] Another node is heartbeating in our slot

Werner van der Walt wrote:
> Thank you very much Sunil. I will give it a try with multiple iSCSI nodes
> then and no host mount and check the results :)
>
> Just another question relating to the number of hosts and nodes. According
to 
> the docs it seems like you can only set up 1 cluster. What if you want a
node 
> to be able to connect to two separate iSCSI hosts serving the same or 
> different OCFS2 block devices. Can that be done? In the config file it
only 
> allows for the one cluster's config and you can only have one config file
per 
> node?

You can have nodes mounting volumes exported by different iscsi hosts,
as long as the volumes exported are different. As in, if two exported 
volumes
are the same, then that won't work.

> Am I then correct in saying that OCFS2 is more of a multi-node
access/usage 
> file system rather than a distributed cluster file system? As I cannot
connect 
> to more than one OCFS2 block device host at the same time it will always
have 
> a one-to-many relationship. If my host dies then the block device dies.
Its 
> not keeping multiple synchronised copies of the block device distributed
over 
> several hosts which I can set up and let it fail-over if one of the hosts 
> dies?

OCFS2 is a shared disk clustered file system. It allows multiple nodes
to concurrently access the file system on a shared device.

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