[Ocfs2-users] Question about eth communication for ocfs2

[Sérgio Surkamp]

Hi,

> Hi,
> 
> I wonder if there is a way to configure two ip_addr in the 
> /etc/ocfs2/cluster.conf
> so that it works on two physically distinct networks, to get the 
> redundancy of
> the link for ocfs2 ?

No.

> (I know there should be  the possibility to use the "bonding" 
> functionnality on
> Ethernet, but I would like not to use it)

Why can't you use bonding? We are using bonding for our iSCSI traffic
and it works very well.

> 
> And a relative question :
> 
>     if there is a network breakdown on the only communication link
> for ocfs2
>     in a two-nodes cluster, what is the behavior :
> 
>     - will both nodes decide to suicide ?
> 
>     - will both nodes remain alive providing the exchanges of 
> informations on disk are always working ?

We have done many tests with iSCSI in our test environment, including
network connectivity loss on both - iSCSI and O2CB networks -, and our
results shows that the slave will fence and the master will recover the
slave journal. When the slave boot, it will not mount the filesystem
due to lack of network connectivity.

The role of master or slave can be any of your nodes, so you can't
predict who will fence.

> 
>     - will both nodes "hang" for ocfs2 rw on FS until network is
> working again on both nodes ?

Yes, until network connectivity is restored or the node fence timeout
configured by O2CB_IDLE_TIMEOUT_MS is reached. If you are using iSCSI,
also consider the O2CB_HEARTBEAT_THRESHOLD.

> 
> Is there a document somewhere describing the behavior of ocfs2 facing
> a list of eventual breakdowns ?

Read the section "13. Heartbeat, Quorum, and Fencing" of the OCFS2
user's guide, it has some information about it.

> 
> Thanks for your response.
> Alain
> 
> 
> 
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Regards,
-- 
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