1.8 KiB
1.8 KiB
Hanoi Ordered Key/Value Storage
Hanoi implements an ordered key/value storage engine, implemented using "doubling sizes" persistent ordered sets of key/value pairs, much like LevelDB.
Here's the bullet list:
- Insert, Delete and Read all have worst case log2(N) latency.
- Incremental space reclaimation: The cost of evicting stale key/values
is amortized into insertion
- you don't need a separate eviction thread to keep memory use low
- you don't need to schedule merges to happen at off-peak hours
- Operations-friendly "append-only" storage
- allows you to backup live system
- crash-recovery is very fast and the logic is straight forward
- Supports efficient range queries
- Riak secondary indexing
- Fast key and bucket listing
- Uses bloom filters to avoid unnecessary lookups on disk
- Efficient resource utilization
- Doesn't store all keys in memory
- Uses a modest number of file descriptors proportional to the number of levels
- IO is generally balanced between random and sequential
- Low CPU overhead
- ~2000 lines of pure Erlang code in src/*.erl
Hanoi is developed by Trifork, a Riak expert solutions provider. You're most welcome to contact us if you want help optimizing your Riak setup.
How to deploy Hanoi as a Riak/KV backend
This storage engine can function as an alternative backend for Basho's Riak/KV.
You can deploy hanoi into a Riak devrel cluster using the enable-hanoi
script. Clone the riak repo, change your working directory to it, and then
execute the enable-hanoi script. It adds hanoi as a dependency, runs make all devrel, and then modifies the configuration settings of the resulting dev
nodes to use the hanoi storage backend.
git clone git://github.com/basho/riak.gitcd riak/depsgit clone git://github.com/basho/hanoi.gitcd .../deps/hanoi/enable-hanoi