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?
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----- 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
> 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.
> 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,
> > pointed out that some of the Configurations he described in his Cassandra
> > Memcached talk (
> > http://www.edwardcapriolo.com/roller/edwardcapriolo/resource/memcache.odp )
> > 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
> > thus making it impossible to spread reads of data from one Region over
> > RegionServers:
> > 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
> > whether it's even mentioned as a limitation, whether there are plans to
> > it or if there are some configuration alternatives that would make some of
> > configurations described by Ed possible with HBase, but I actually didn't
> > any explicit information about that.
> > Would anyone care to comment? :)
> > Many thanks,
> > Otis
> > --
> > We're hiring HBase hackers for Data Mining and Analytics