droonga/droonga-engine — pull request #30 by piroor (2014-12-04 11:59:00+00:00)
Title: Support replicas in a slice

Currently, only RAID 0+1 like fragile cluster is supported.
For safety, each slice in slices should be replicable, like RAID 1+0.
(However, top-level replicas must be there even if RAID 1+0 like structure is supported, because it is useful to migrate an existing slice to new one.)

ex:

replicas: [
{ // replica
slices: [
{ // slice
replicas: [
{ volume: ... }, // replica of a slice
{ volume: ... }
]
}
]
}
]

See also: http://itpro.nikkeibp.co.jp/article/Watcher/20060518/238330/