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/ >
