[Ocfs2-devel] [PATCH 3/3] o2net: correct keepalive message protocol
Srinivas Eeda
srinivas.eeda at oracle.com
Wed Feb 17 14:52:26 PST 2010
No harm, just doubles heartbeat messages which is not required at all.
Sunil Mushran wrote:
> What's the harm in leaving it in?
>
> Srinivas Eeda wrote:
>> Each node that has this patch would send a O2NET_MSG_KEEP_REQ_MAGIC
>> every 2 seconds(default). So, nodes without this patch would always
>> receive a heartbeat message every 2 seconds.
>>
>> Nodes without this patch will send(respond) with
>> O2NET_MSG_KEEP_RESP_MAGIC for every keep alive packet they received.
>> So nodes with this patch will always receive a response message.
>>
>> So, in a mixed setup, both nodes will always hear the heartbeat from
>> each other :).
>>
>> thanks,
>> --Srini
>>
>>
>>
>> Joel Becker wrote:
>>
>>> On Thu, Jan 28, 2010 at 08:51:11PM -0800, Srinivas Eeda wrote:
>>>
>>>> case O2NET_MSG_KEEP_REQ_MAGIC:
>>>> - o2net_sendpage(sc, o2net_keep_resp,
>>>> - sizeof(*o2net_keep_resp));
>>>> + /* Each node now sends keepalive message every
>>>> + * keepalive time interval. Hence no need for response
>>>> + */
>>>> goto out;
>>>>
>>> You still have to send the response. Think about a mixed
>>> environment where some nodes have this fix and some do not. The older
>>> software is still waiting on the response.
>>> The newer version can just ignore any responses it gets from
>>> other nodes. But it has to send responses out just in case the other
>>> node is older.
>>> The only other alternative is to bump the o2net protocol
>>> version, and that means the cluster has to be shut down to upgrade.
>>> Not
>>> a good choice.
>>>
>>> Joel
>>>
>>>
>>
>>
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>
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