I have one more question. Based on some tests, some workers totally shut down and re-run, which means each task lost all the data. Some workers do not shut down and are resumed after rebalance, which means each task keeps the data.
So, I assume Storm has some capabilities to distinguish them based on input parameter for rebalancing. What is the condition to decide this? Thanks, Junguk 2016-08-11 17:33 GMT-04:00 Junguk Cho <jman...@gmail.com>: > Hi. > > Thank you for replies. > Now, it worked. > > 2. second, you should make sure your topology has been assigned more than > 10 task. because the rebalacing is based on the task to do more workers. If > you did not assigne 10 tasks(at least) to the topology explicitly, the > rebalancing can not work out as you want. > -> Yes. I re-interpret that "rebalance function" is redistributing tasks > into executors. > > I have one following question. > I don't see some benefits to have multiple tasks in one executor since one > executor is a java thread and multiple tasks run in sequence based on a > grouping. > > Does anyone explain when we can get benefit from multiple tasks? > > > Thanks, > Junguk > > 2016-08-11 1:13 GMT-04:00 fanxi...@travelsky.com <fanxi...@travelsky.com>: > >> hi Junquk： >> >> 1. first, you should make sure your cluster has more than 10 slots. >> 2. second, you should make sure your topology has been assigned more than >> 10 task. because the rebalacing is based on the task to do more workers. If >> you did not assigne 10 tasks(at least) to the topology explicitly, the >> rebalancing can not work out as you want. >> >> >> ------------------------------ >> >> >> >> >> *From:* Junguk Cho <jman...@gmail.com> >> *Date:* 2016-08-11 11:09 >> *To:* user <user@storm.apache.org> >> *Subject:* STORM REBALACING >> Hi, All. >> >> I tried to use STORM rebalance (http://storm.apache.org/relea >> ses/1.0.1/Command-line-client.html). >> >> I used Storm 1.0.1 version. >> I first ran 3 workers (one spout, one split and one count.) for WordCount >> example. >> >> After running it, In commandline, I typed >> ./storm rebalance WordCount -w 10 -n 6 -e spout=1 -e split=2 -e count=2 >> >> I saw something in nimbus.log and UI like >> Delaying event :do-rebalance for 10 secs for WordCount-1-1470884051. >> However, when I checked UI, it was still 3 workers. >> >> >> Are there some requirements to use rebalance feature? >> Also, in UI, there are no input interfaces to specify # of workers and # >> of components except for waiting time for rebalace. >> >> >> Thanks in advance. >> - Junguk >> >> >
