Hi Raymond, Yes, tables are balanced on by one. Balancer is taking one table, looking if it's already balancer or not, do the required move if any is needed, and then move to the next table.
In your example, average is 23.25. 20% is 4.65. So everything between 18.6 and 27.9 should be ok. So balancer should remove some regions for the 3rd server (19 i/30/23/21). If you want to have that more evenly balanced, reduce the hbase.regions.slop value to something lower, like 0.1 or even 0.05. Don't go too low else it will never stop balancing the table each 5 minutes. JM 2013/2/20, Liu, Raymond <raymond....@intel.com>: > You mean slop is also base on per table? > Weird, then it should work for my case.... let me check again. > > Best Regards, > Raymond Liu > >> >> bq. On a 3000 region cluster >> >> Balancing is per-table. Meaning total number of regions doesn't come into >> play. >> >> On Tue, Feb 19, 2013 at 7:55 PM, Liu, Raymond <raymond....@intel.com> >> wrote: >> >> > Hmm, in order to have the 96 region table be balanced within 20% On a >> > 3000 region cluster when all other table is balanced. >> > >> > the slop will need to be around 20%/30, say 0.006? won't it be too >> > small? >> > >> > > >> > > Yes, Raymond. >> > > You should lower sloppiness. >> > > >> > > On Tue, Feb 19, 2013 at 7:48 PM, Liu, Raymond >> > > <raymond....@intel.com> >> > > wrote: >> > > >> > > > I mean region number is small. >> > > > >> > > > Overall I have say 3000 region on 4 node, while this table only >> > > > have >> > > > 96 region. It won't be 24 for each region server, instead , will >> > > > be something like 19/30/23/21 etc. >> > > > >> > > > This means that I need to limit the slop to 0.02 etc? so that the >> > > > balancer actually run on this table? >> > > > >> > > > Best Regards, >> > > > Raymond Liu >> > > > >> > > > From: Marcos Ortiz [mailto:mlor...@uci.cu] >> > > > Sent: Wednesday, February 20, 2013 11:44 AM >> > > > To: user@hbase.apache.org >> > > > Cc: Liu, Raymond >> > > > Subject: Re: Is there any way to balance one table? >> > > > >> > > > What is the size of your table? >> > > > On 02/19/2013 10:40 PM, Liu, Raymond wrote: >> > > > Hi >> > > > >> > > > I do call balancer, while it seems it doesn't work. Might due to >> > > > this table is small and overall region number difference is within >> > threshold? >> > > > >> > > > -----Original Message----- >> > > > From: Jean-Marc Spaggiari [mailto:jean-m...@spaggiari.org] >> > > > Sent: Wednesday, February 20, 2013 10:59 AM >> > > > To: user@hbase.apache.org >> > > > Subject: Re: Is there any way to balance one table? >> > > > >> > > > Hi Liu, >> > > > >> > > > Why did not you simply called the balancer? If other tables are >> > > > already balanced, it should not touch them and will only balance >> > > > the table which is not balancer? >> > > > >> > > > JM >> > > > >> > > > 2013/2/19, Liu, Raymond <raymond....@intel.com>: >> > > > I choose to move region manually. Any other approaching? >> > > > >> > > > >> > > > 0.94.1 >> > > > >> > > > Any cmd in shell? Or I need to change balance threshold to 0 an >> > > > run global balancer cmd in shell? >> > > > >> > > > >> > > > >> > > > Best Regards, >> > > > Raymond Liu >> > > > >> > > > -----Original Message----- >> > > > From: Ted Yu [mailto:yuzhih...@gmail.com] >> > > > Sent: Wednesday, February 20, 2013 9:09 AM >> > > > To: user@hbase.apache.org >> > > > Subject: Re: Is there any way to balance one table? >> > > > >> > > > What version of HBase are you using ? >> > > > >> > > > 0.94 has per-table load balancing. >> > > > >> > > > Cheers >> > > > >> > > > On Tue, Feb 19, 2013 at 5:01 PM, Liu, Raymond >> > > > <raymond....@intel.com> >> > > > wrote: >> > > > >> > > > Hi >> > > > >> > > > Is there any way to balance just one table? I found one of my >> > > > table is not balanced, while all the other table is balanced. So I >> > > > want to fix this table. >> > > > >> > > > Best Regards, >> > > > Raymond Liu >> > > > >> > > > >> > > > >> > > > >> > > > -- >> > > > Marcos Ortiz Valmaseda, >> > > > Product Manager && Data Scientist at UCI >> > > > Blog: http://marcosluis2186.posterous.com >> > > > Twitter: @marcosluis2186 >> > > > >> > >
