if id, err = pools.initRebalanceMeta(ctx, buckets); err != nil {
		writeErrorResponseJSON(ctx, w, toAPIError(ctx, err), r.URL)
		return
	}

	// Rebalance routine is run on the first node of any pool participating in rebalance.
	pools.StartRebalance()

	b, err := json.Marshal(struct {
		ID string `json:"id"`
	}{ID: id})
	if err != nil {
		writeErrorResponseJSON(ctx, w, toAPIError(ctx, err), r.URL)
		return

	NumVersions       uint64        `json:"numVersions" msg:"nv"`        // Number of versions rebalanced
	Bytes             uint64        `json:"bytes" msg:"bs"`              // Number of bytes rebalanced
	Participating     bool          `json:"participating" msg:"par"`
	Info              rebalanceInfo `json:"info" msg:"inf"`
}

func (rs *rebalanceStats) update(bucket string, fi FileInfo) {
	if fi.IsLatest {
		rs.NumObjects++
	}

	// mainly set for certain WRITE operations.
	SkipDecommissioned bool
	// SkipRebalancing should be set to 'true' if the call should skip pools
	// participating in a rebalance operation. Typically set for 'write' operations.
	SkipRebalancing bool

	SrcPoolIdx int // set by PutObject/CompleteMultipart operations due to rebalance; used to prevent rebalance src, dst pools to be the same