Please see HBASE-4298 where this feature was introduced. On Tue, Apr 26, 2016 at 5:12 AM, WangYQ <wangyongqiang0...@163.com> wrote:
> yes, there is a tool graceful_stop.sh to graceful stop regionserver, and > can move the regions back to the rs after rs come back. > but i can not find the relation with drain region servers... > > > i think drain region servers function is good, but can not think up with a > pracital use case > > > > > > > > > At 2016-04-26 16:01:55, "Dejan Menges" <dejan.men...@gmail.com> wrote: > >One of use cases we use it is graceful stop of regionserver - you unload > >regions from the server before you restart it. Of course, after restart > you > >expect HBase to move regions back. > > > >Now I'm not really remembering correctly, but I kinda remember that one of > >the features was at least that it will move back regions which were > already > >there, hence not destroy too much block locality. > > > >On Tue, Apr 26, 2016 at 8:15 AM WangYQ <wangyongqiang0...@163.com> wrote: > > > >> thanks > >> in hbase 0.99.0, I find the rb file: draining_servers.rb > >> > >> > >> i have some suggestions on this tool: > >> 1. if I add rs hs1 to draining_servers, when hs1 restart, the zk node > >> still exists in zk, but hmaster will not treat hs1 as draining_servers > >> i think when we add a hs to draining_servers, we do not need to > store > >> the start code in zk, just store the hostName and port > >> 2. we add hs1 to draining_servers, but if hs1 always restart, we will > >> need to add hs1 several times > >> when we need to delete the draining_servers info of hs1, we will > need > >> to delete hs1 several times > >> > >> > >> > >> finally, what is the original motivation of this tool, some scenario > >> descriptions are good. > >> > >> > >> > >> > >> > >> > >> At 2016-04-26 11:33:10, "Ted Yu" <yuzhih...@gmail.com> wrote: > >> >Please take a look at: > >> >bin/draining_servers.rb > >> > > >> >On Mon, Apr 25, 2016 at 8:12 PM, WangYQ <wangyongqiang0...@163.com> > >> wrote: > >> > > >> >> in hbase, I find there is a "drain regionServer" feature > >> >> > >> >> > >> >> if a rs is added to drain regionServer in ZK, then regions will not > be > >> >> move to on these regionServers > >> >> > >> >> > >> >> but, how can a rs be add to drain regionServer, we add it handly > or > >> rs > >> >> will add itself automaticly > >> >
