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HBase, mail # user - Region replication?


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Re: Region replication?
Otis Gospodnetic 2011-04-19, 21:26
Thanks J-D!

Yeah, what you describe below is also something that I think Edward pointed out
in some of his slides - that you could route all requests for X to the place
where X is when you don't want to have X cached (in app-level caches and/or
OS-level caches) on multiple servers, but that sometimes you do want to "waste"
memory like this because you have to spread requests for X over more servers.

Are these two modes going to be supported in HBase?

Thanks,
Otis
----
We're hiring HBase hackers for Data  Mining and Analytics
http://blog.sematext.com/2011/04/18/hiring-data-mining-analytics-machine-learning-hackers/

----- Original Message ----
> From: Jean-Daniel Cryans <[EMAIL PROTECTED]>
> To: [EMAIL PROTECTED]
> Sent: Tue, April 19, 2011 5:10:07 PM
> Subject: Re: Region replication?
>
> We have something on the menu:
> https://issues.apache.org/jira/browse/HBASE-2357 Coprocessors:  Add
> read-only region replicas (slaves) for availability and fast  region
> recovery
>
> Something to keep in mind is that you have to cache  the data for each
> replica, so a row could be in 3 different caches (which  also have to
> be warmed). I guess this is useful for very hot rows compared to  a
> much larger read distribution, in which case you'd really want to
> cache  it only once else you'd need 3x the memory to hold your dataset
> in  cache.
>
> J-D
>
> On Tue, Apr 19, 2011 at 12:33 PM, Otis  Gospodnetic
> <[EMAIL PROTECTED]>  wrote:
> > Hi,
> >
> > I imagine lots of HBase folks have read or  will want to read
> > http://blog.milford.io/2011/04/why-i-am-very-excited-about-datastaxs-brisk/
,
> > including comments.
> >
> > My question has to do with one of  the good comments from Edward Capriolo,
>who
> > pointed out that  some of  the Configurations he described in his Cassandra
> as
> > Memcached talk  (
> > http://www.edwardcapriolo.com/roller/edwardcapriolo/resource/memcache.odp )  
>are
> > not possible with HBase because in HBase there is only 1 copy of any  given
> > Region and it lives on a single RegionServer (I'm assuming this is  
>correct?),
> > thus making it impossible to spread reads of data from one  Region over
>multiple
> > RegionServers:
> >
> >
>http://blog.milford.io/2011/04/why-i-am-very-excited-about-datastaxs-brisk/#comment-187253604
>
> >
> >
> >  So I poked around on search-hadoop.com and JIRA, and looked at
> > http://hbase.apache.org/book/regions.arch.html to see about this  
limitation,
> > whether it's even mentioned as a limitation, whether there  are plans to
>change
> > it or if there are some configuration alternatives  that would make some of
>those
> > configurations described by Ed possible  with HBase, but I actually didn't
>find
> > any explicit information about  that.
> >
> > Would anyone care to comment? :)
> >
> > Many  thanks,
> > Otis
> > --
> > We're hiring HBase hackers for Data  Mining and Analytics
> >
>http://blog.sematext.com/2011/04/18/hiring-data-mining-analytics-machine-learning-hackers/
>
> >
>