Does this mean we have to listen to events of server nodes going up and down and activate and deactivate the cluster?
On Wed, Aug 2, 2017 at 3:18 PM, Michael Cherkasov < michael.cherka...@gmail.com> wrote: > when all nodes are up, so in latest topology snapshot you can see servers > count == servers count you run, then cluster can be activated. > > 2017-08-02 0:51 GMT+03:00 Raymond Wilson <raymond_wil...@trimble.com>: > >> Hi Mikhail, >> >> >> >> Thanks for the clarifications. >> >> >> >> Yes, I knew setting active was only required when using the persistence >> layer, which is the topic of the question J >> >> >> >> I was interested if there were best practices or approaches for >> determining when the grid had fully initialized. I realise this is somewhat >> application specific, but was looking for an established pattern before I >> invented one myself. >> >> >> >> In my case I have an affinity function that responds to topology changes >> which intrinsically would know when it had a ‘quorum’. Is this a typical >> place for setting active to true. >> >> >> >> Thanks, >> >> Raymond. >> >> >> >> *From:* Mikhail Cherkasov [mailto:mcherka...@gridgain.com] >> *Sent:* Tuesday, August 1, 2017 11:59 PM >> *To:* user@ignite.apache.org >> *Subject:* Re: Best practise for setting Ignite.Active to true when >> using persistence layer in Ignite 2.1 >> >> >> >> Hi Raymond, >> >> >> >> Ignite cluster is inactive on startup only if persistence is enabled. >> This is done to avoid unnecessary partition exchanges between nodes, >> >> for example, if you have 3 nodes and 1 backup enabled and you start only >> 2 of 3 nodes, then they will treat the third node as dead and start process >> >> of restoring data from backup and rebalance data to spread them among 2 >> nodes, when you add the missed third node back the process will be repeated. >> >> >> >> So we start cluster as in active. When all nodes are started and ready, >> so no cluster topology changes aren't expected, you should activate cluster. >> >> >> >> Also when you turn off cluster, some nodes can still accept request for >> data update and other nodes won't see it, so understand which node has the >> latest >> >> data we need to start all nodes first and only then activate cluster. >> >> >> >> Thanks, >> >> Mikhail. >> >> >> >> On Tue, Aug 1, 2017 at 5:05 AM, Raymond Wilson < >> raymond_wil...@trimble.com> wrote: >> >> Hi, >> >> >> >> I am experimenting with a POC looking into using the Ignite persistence >> layer. >> >> >> >> One aspect of this is setting the grid to be ‘Active’ after all cache >> grid nodes have instantiated. >> >> >> >> In practical terms, what is the best practice for ensuring the cluster is >> running and in a good state to be set to active? What is the downside of >> setting active to true before all grid nodes are running? >> >> >> >> Thanks, >> >> Raymond. >> >> >> >> >> >> >> >> -- >> >> Thanks, >> >> Mikhail. >> > >
