43 lines
1.8 KiB
Markdown
43 lines
1.8 KiB
Markdown
# 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 log<sub>2</sub>(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
|
|
- 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.
|
|
|
|
1. `git clone git://github.com/basho/riak.git`
|
|
1. `cd riak/deps`
|
|
1. `git clone git://github.com/basho/hanoi.git`
|
|
1. `cd ..`
|
|
1. `./deps/hanoi/enable-hanoi`
|