leveled/priv/leveled_multi.schema

%% -*- erlang -*-

%%%% leveled

%% @doc A path under which leveled data files will be stored.
{mapping, "multi_backend.$name.leveled.data_root", "riak_kv.multi_backend", [
  {default, "$(platform_data_dir)/leveled"},
  {datatype, directory},
  hidden
]}.

%% @doc Strategy for flushing data to disk
%% Can be set to riak_sync, sync (if OTP > 16) or none.  Use none, and the OS
%% will flush when most efficient.  Use riak_sync or sync to flush after every
%% PUT (not recommended without some hardware support e.g. flash drives and/or
%% Flash-backed Write Caches) 
{mapping, "multi_backend.$name.leveled.sync_strategy", "riak_kv.multi_backend", [
  {default, none},
  {datatype, atom},
  hidden
]}.


%% @doc The key size of the Bookie's in-memory cache 
{mapping, "multi_backend.$name.leveled.cache_size", "riak_kv.multi_backend", [
  {default, 2000},
  {datatype, integer},
  hidden
]}.

%% @doc The key size of the Penciller's in-memory cache
{mapping, "multi_backend.$name.leveled.penciller_cache_size", "riak_kv.multi_backend", [
  {default, 20000},
  {datatype, integer},
  hidden
]}.

%% @doc Compression method
%% Can be lz4 or native (which will use the Erlang native zlib compression)
%% within term_to_binary
{mapping, "multi_backend.$name.leveled.compression_method", "riak_kv.multi_backend", [
  {default, lz4},
  {datatype, atom},
  hidden
]}.

%% @doc Compression point
%% The point at which compression is applied to the Journal (the Ledger is 
%% always compressed).  Use on_receipt or on_compact.  on_compact is suitable
%% when values are unlikely to yield much benefit from compression 
%% (compression is only attempted when compacting)
{mapping, "multi_backend.$name.leveled.compression_point", "riak_kv.multi_backend", [
  {default, on_receipt},
  {datatype, atom},
  hidden
]}.


%% @doc The approximate size (in bytes) when a Journal file should be rolled.
%% Normally keep this as around the size of o(100K) objects.  Default is 1GB.
%% Note that on startup an actual maximum size will be chosen which varies by
%% a random factor from this point - to avoid coordination of roll events
%% across vnodes.
{mapping, "multi_backend.$name.leveled.journal_size", "riak_kv.multi_backend", [
  {default, 1000000000},
  {datatype, integer}
]}.

%% @doc The approximate count of objects when a Journal file should be rolled.
%% This time measured in object count, a file will be rolled if either the
%% object count or the journal size limit is reached.  Default 200K.
%% Note that on startup an actual maximum size will be chosen which varies by
%% a random factor from this point - to avoid coordination of roll events
%% across vnodes.
{mapping, "multi_backend.$name.leveled.journal_objectcount", "riak_kv.multi_backend", [
  {default, 200000},
  {datatype, integer}
]}.

%% @doc The level of the ledger to be pre-loaded into the page cache
%% Depending on how much memory is available for the page cache, and how much
%% disk I/O activity can be tolerated at startup - then the level at which the
%% ledger is forced into the page cache can be controlled by configuration.
{mapping, "multi_backend.$name.leveled.ledger_pagecachelevel", "riak_kv.multi_backend", [
  {default, 4},
  {datatype, integer}
]}.


%% @doc The number of journal compactions per vnode per day
%% The higher the value, the more compaction runs, and the sooner space is 
%% recovered.  But each run has a cost
{mapping, "multi_backend.$name.leveled.compaction_runs_perday", "riak_kv.multi_backend", [
  {default, 24},
  {datatype, integer},
  hidden
]}.

%% @doc The number of times per day to score an individual file for compaction
%% The default value will lead to each file, on average, being scored once
%% every 12 hours
{mapping, "multi_backend.$name.leveled.compaction_scores_perday", "riak_kv.multi_backend", [
  {default, 2},
  {datatype, integer}
]}.

%% @doc Compaction Low Hour
%% The hour of the day in which journal compaction can start.  Use Low hour 
%% of 0 and High hour of 23 to have no compaction window (i.e. always compact 
%% regardless of time of day)
{mapping, "multi_backend.$name.leveled.compaction_low_hour", "riak_kv.multi_backend", [
  {default, 0},
  {datatype, integer},
  hidden
]}.

%% @doc Compaction Top Hour
%% The hour of the day, after which journal compaction should stop.
%% If low hour > top hour then, compaction will work overnight between low
%% hour and top hour (inclusive).  Timings rely on server's view of local time
{mapping, "multi_backend.$name.leveled.compaction_top_hour", "riak_kv.multi_backend", [
  {default, 23},
  {datatype, integer},
  hidden
]}.

%% @doc Max Journal Files Per Compaction Run
%% In a single compaction run, what is the maximum number of consecutive files
%% which may be compacted.  If increasing this value, the average number of
%% files per run may decrease, unless adjustments are also made to the
%% maxrunlength and singlefile compactionpercentage settings.
{mapping, "multi_backend.$name.leveled.max_run_length", "riak_kv.multi_backend", [
  {default, 4},
  {datatype, integer},
  hidden
]}.

%% @doc Target Percentage for Max Run
%% What is the target score for a maximum run of files, to qualify for 
%% compaction.  If less than this percentage would be retained after compaction
%% then it is a candidate (e.g. in default case if 25% of space would be
%% recovered)
{mapping, "multi_backend.$name.leveled.maxrunlength_compactionpercentage", "riak_kv.multi_backend", [
  {default, 75.0},
  {datatype, float},
  hidden
]}.

%% @doc Target Percentage for Single File
%% What is the target score for a run of a single file, to qualify for 
%% compaction.  If less than this percentage would be retained after compaction
%% then it is a candidate (e.g. in default case if 25% of space would be
%% recovered)
{mapping, "multi_backend.$name.leveled.singlefile_compactionpercentage", "riak_kv.multi_backend", [
  {default, 25.0},
  {datatype, float},
  hidden
]}.


%% @doc Snapshot timeout (short)
%% Maximum expected time for an index query.  A query which is taking longer
%% than this may fail as it will be released - potentially allowing for some
%% file processes to delete.  Timeout is in seconds.
{mapping, "multi_backend.$name.leveled.snapshot_timeout_short", "riak_kv.multi_backend", [
  {default, 1800},
  {datatype, integer},
  hidden
]}.

%% @doc Snapshot timeout (long)
%% Maximum expected time for any other fold.  A fold which is taking longer
%% than this may fail as it will be released - potentially allowing for some
%% file processes to delete.  Timeout is in seconds.
{mapping, "multi_backend.$name.leveled.snapshot_timeout_long", "riak_kv.multi_backend", [
  {default, 86400},
  {datatype, integer},
  hidden
]}.