By the way, where can I get a stable version of 0.90? Thanks.
Cao On Wed, Oct 6, 2010 at 12:54 PM, Jean-Daniel Cryans <[email protected]>wrote: > Like Stack said, it's available in 0.90 which we're currently wrapping > up (so not in 0.20.x). > > Distributing regions and distributing blocks is orthogonal (ish, but > for this discussion let's not mix the two together), the former being > assumed by the HBase master and the latter being assumed by the > Namenode. Maybe this blog post can help you understanding how HBase > uses HDFS > http://www.larsgeorge.com/2009/10/hbase-architecture-101-storage.html > > J-D > > On Tue, Oct 5, 2010 at 8:38 PM, William Kang <[email protected]> > wrote: > > So, I can use the 'move' command to manually balance the load? Is this > > available to 0.20.6? Was there any automatic balance mechanism in hbase > > before if the replicated block is not for load distribution purpose? > Thanks. > > > > > > William > > > > On Tue, Oct 5, 2010 at 11:19 PM, Stack <[email protected]> wrote: > > > >> In 0.90, you can turn off the balancer and then distribute the regions > >> any way you wish with new 'move' command. > >> St.Ack > >> > >> On Tue, Oct 5, 2010 at 8:13 PM, Jean-Daniel Cryans <[email protected] > > > >> wrote: > >> > A row is always served a single region, so the question is more about > >> > region distribution. In 0.20 and 0.89 you have no control over that > >> > (the best you can do is calling close_region in the shell, where is > >> > the region will be moved is "random"), but things are getting better > >> > in 0.90 where you'll be able to move regions manually. > >> > > >> > HBase doesn't create multiple copies of HFiles to distribute load, > >> > what happens is each block is replicated 3 times by HDFS and this is > >> > invisible to HBase. This is done for data safety rather than > >> > distributing the load. > >> > > >> > J-D > >> > > >> > On Tue, Oct 5, 2010 at 8:05 PM, William Kang <[email protected]> > >> wrote: > >> >> Hi folks, > >> >> I have a general question about Hbase. Can we pick which region > server > >> we > >> >> want to save a particular row? The reason I am asking this is because > >> >> sometimes we want to manually balance region servers' load. If we > could > >> >> assign particular rows to particular region servers, we can have that > >> >> control. I understand that Hbase will balance its load automatically > by > >> >> create multiple copies of hfiles in HDFS. But, we do want to have > more > >> >> control over that. Is it possible or is it already in Hbase but we > >> didn't > >> >> find it? Many thanks. > >> >> > >> >> > >> >> William > >> >> > >> > > >> > > >
