Hi Brian, Experimental backends for Riak are always exciting. I haven't played with it personally, and Basho has no current plans to support it as a leveldb alternative.
It's worth adding two notes of caution. First, stores that use mmap for persistence can suffer from problems around dirty pages. If you have a very low update volume and a nice hot set that the operating system can keep the pages in memory they work nicely. On some operating systems (specifically Linux), if you have a high update load, and consequently a large volume of dirty pages (more than dirty_ratio), I believe all OS level threads for the process are suspended until the condition is resolved by writing out the pages when the process is scheduled. This is bad for latencies in endurance tests. For something like LDAP this tradeoff is probably a good one, for Riak it concerns me, and other platforms may be better behaved to make the option interesting, and the linux kernel may have begun Second, I worry about crash resilience - can the internal memory structures tolerate a kernel panic where the dirty pages are not written, or potentially worse torn with a partial write. Good luck with your experiments, Jon On Wed, May 1, 2013 at 11:05 AM, Brian Hong <[email protected]> wrote: > OpenLDAP Lightning Memory-Mapped Database seems to be getting traction for > it's high performance and similar query (iteration) functionality with > leveldb: > http://symas.com/mdb/ > > There seems to be an experimental backend for Riak: > > https://github.com/alepharchives/emdb > > Does anybody know of it's usefulness? Is there any benchmarks on it? > > I've heard that leveldb suffers write performance issues: > https://news.ycombinator.com/item?id=5621884 > > Any chances of Basho guys supporting lmdb as an leveldb alternative to > Riak? It would be awesome! :D > > -- > Brian(Sung-jin) Hong > > _______________________________________________ > riak-users mailing list > [email protected] > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com > > -- Jon Meredith VP, Engineering Basho Technologies, Inc. [email protected]
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