Hello, Alex!
I think it is a great idea.
I suggest to build communications between nodes on weight (or priority).
For example, ordering on latency:
- nodes on one host = 1
- nodes in one rack-blade = 2
- nodes in one server-rack = 3
- nodes in one physical cluster = 4
- nodes in one subnet = 5
- etc.
Maybe it'll be better to use some metrics from ClusterMetrics interface.
The algorithm of ordering can be implemented in a class such as Comparator
and use it when we build a cluster or we select a place for a new node.
--
With best regards,
Vyacheslav Daradur
2016-12-22 13:59 GMT+03:00 Александр Меньшиков <sharple...@gmail.com>:
> Hello everyone,
>
> As far as I know nodes are connected in a ring. For example if i have 6
> nodes, with names A, B, C, D, E, and F they can connect in ring any
> possible way: A-B-C-D-E-F-A, or A-F-B-E-C-D-A, etc. And if some node falls
> out of topology neighboring nodes must reconnect. If nodes A,B and C
> located in the same physical location, and D, E and F in another, and in
> some time one physical location is not available in another, we can get
> different number of reconnections. Best case scenario if we have ring like
> A-B-CxD-E-FxA ('x' mean disconnect) -- then we get only one reconnect (C
> reconnect to A or F reconnect to D -- depending on what part of the cluster
> we leave alive). But now possible that case AxFxBxExCxDxA -- then we get a
> lot of reconnections (A to B, B to C, C to A -- in general n/2
> reconnections, where n -- number of nodes). And i think to add something to
> ensure that we always have good sorting of nodes connections
> (A-B-C-...-Z-A).
>
> Of course in real world we can have multiple levels of physical closeness.
>
> In my opinion enough to add one parameter of 'int' to configuration (with
> name like 'ExtraNodeOrder') and to change the method of comparison nodes so
> that it first compared the 'ExtraNodeOrder', and then according to the old
> criterion (as far as I know Ignite use topology version). So if some users
> have multiple levels of physical closeness, he can use different bits. For
> example use 16 high bits for DC number, and low 16 bits for racks.
>
> Alternatively, we can add array of ‘int’ to configuration and compare nodes
> in sequence from the zero element to the last.
>
