Re: Re: Re: question on "drain region servers"
Please see HBASE-4298 where this feature was introduced. On Tue, Apr 26, 2016 at 5:12 AM, WangYQ 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" 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 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" wrote: > >> >Please take a look at: > >> >bin/draining_servers.rb > >> > > >> >On Mon, Apr 25, 2016 at 8:12 PM, WangYQ > >> 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 > >> >
Re:Re: Re: question on "drain region servers"
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" 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 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" wrote: >> >Please take a look at: >> >bin/draining_servers.rb >> > >> >On Mon, Apr 25, 2016 at 8:12 PM, WangYQ >> 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 >>
Re: Re: question on "drain region servers"
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 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" wrote: > >Please take a look at: > >bin/draining_servers.rb > > > >On Mon, Apr 25, 2016 at 8:12 PM, WangYQ > 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 >
Re: question on "drain region servers"
Please take a look at: bin/draining_servers.rb On Mon, Apr 25, 2016 at 8:12 PM, WangYQ 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
