cachevalue.Opts{ReturnLastGood: true, NoWait: true},
		func() (map[string]uint64, error) {
			m := make(map[string]uint64)
			for _, pool := range z.serverPools {
				for _, er := range pool.sets {
					// Load bucket usage prefixes
					ctx, done := context.WithTimeout(context.Background(), 2*time.Second)
					ok := cache.load(ctx, er, bucket+slashSeparator+dataUsageCacheName) == nil
					done()
					if ok {
						root := cache.find(bucket)