[Linux-ha-dev] More commit comments
zhenhltc at cn.ibm.com
Sun Oct 8 06:54:59 MDT 2006
Lars Marowsky-Bree wrote:
> On 2006-10-02T21:03:14, Huang Zhen <zhenhltc at cn.ibm.com> wrote:
>> 2_0_8 is the protocol version. Different versons of heartbeat may
>> share one same protocol. When we add a new implementation, we just
>> need put a new plugin with the new version. And when the client
>> connects it will send the version of protocol. quorumd will call
>> different plugin according to the version of protocol.
> Well, versioned protocols clearly make sense, but I'm not sure this path
> is the best. You'll need to translate between protocol versions, if one
> subcluster is on a different version than the other, no?
Because the different version of protocols may use different vote data set,
the quorum can't be calculated when the two subclusters using different
protocols. We can let the quorumd return NOQUORUM in this situation ( not
To upgrade, if the cluster is in split-brain situation, the service would
be stopped during the upgrading (for the quroumd returns NOQUROUM).
And if the cluster is not in split-brain status, then only one node (DC) is
connecting to the quorum server, then this would not be a problem.
> How do the clients determine which version needs to be used when
> connecting to a server?
Yeah, this part the code should be improved.
we can let the server sends the version list it supporting to client when
client connected, then the clients choose one and send the version it likes
to use back to the server. This may make the upgrading more flexible.
> Lars Marowsky-Brée
Linux-HA, Linux Technology Center, China Systems & Technology Lab
China Development Labs, Beijing Tel: 86-10-82782244 Ext. 2845
Email: zhenhltc at cn.ibm.com
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