BGSAVE
Start a snapshot save in the background.
BGSAVEComplexity
O(S) fan-out; O(N/S) copy-on-write freeze per shard on the reactor, then serialise off-thread
Complexity and compatibility are read out of kevy's implementation, not copied from Redis's reference. Several genuinely differ.
Redis compatibility
Differs
replies +OK rather than Redis's status line, and writes one dump per shard
See also
BGREWRITEAOFCLIENTCLUSTERCOMMANDCONFIGDBSIZEDEBUGFLUSHALLFLUSHDBINFOMEMORYSAVESHUTDOWNSLOWLOG