~~ specific language governing permissions and limitations
~~ under the License.

  ---
  Offline Mode Design
  ---
  John Casey
  ---
  2005-04-08
  ---

Offline Mode Design

* UPDATE: 18-April-2005

  We cannot take the approach outlined below of detecting which remote
  repositories are "really" offline, since offline mode is more of a behavior,

	// If not set the client will not keep track of health.
	// Calling this returns true or false if the target
	// is online or offline.
	HealthCheckFn func() bool

	// HealthCheckRetryUnit will be used to calculate the exponential
	// backoff when trying to reconnect to an offline node
	HealthCheckReconnectUnit time.Duration

	// HealthCheckTimeout determines timeout for each call.
	HealthCheckTimeout time.Duration

package cmd

import "context"

const (
	healthDrivesOfflineCount = "drives_offline_count"
	healthDrivesOnlineCount  = "drives_online_count"
	healthDrivesCount        = "drives_count"
)

var (
	healthDrivesOfflineCountMD = NewGaugeMD(healthDrivesOfflineCount,
		"Count of offline drives in the cluster")
	healthDrivesOnlineCountMD = NewGaugeMD(healthDrivesOnlineCount,

        this.loggingLevel = loggingLevel;

        return this;
    }

    @Override
    public MavenExecutionRequest setOffline(boolean offline) {
        this.offline = offline;

        return this;
    }

    @Override
    public MavenExecutionRequest setUpdateSnapshots(boolean updateSnapshots) {
        this.updateSnapshots = updateSnapshots;

| `minio_cluster_replication_link_online`                    | Reports whether the replication link is online (1) or offline (0).                                       |
| `minio_cluster_replication_link_offline_duration_seconds`  | Total duration of replication link being offline in seconds since last offline event                     |

			nil, nil),
		prometheus.GaugeValue,
		float64(GetTotalUsableCapacityFree(server.Disks, sinfo)),
	)

	// MinIO Offline Disks per node
	ch <- prometheus.MustNewConstMetric(
		prometheus.NewDesc(
			prometheus.BuildFQName(minioNamespace, "disks", "offline"),
			"Total number of offline drives in current MinIO server instance",
			nil, nil),
		prometheus.GaugeValue,
		float64(offlineDisks.Sum()),
	)

| `minio_cluster_health_drives_offline_count`        | `gauge` | Count of offline drives in the cluster         |        |
| `minio_cluster_health_drives_online_count`         | `gauge` | Count of online drives in the cluster          |        |
| `minio_cluster_health_drives_count`                | `gauge` | Count of all drives in the cluster             |        |

					var lastOnline time.Time
					var offline time.Duration
					//	var deploymentID string
					sys.hMutex.RLock()
					prev, ok := sys.hc[result.Endpoint.Host]
					sys.hMutex.RUnlock()
					if ok {
						if prev.Online != result.Online || !result.Online {
							if !prev.lastHCAt.IsZero() {
								offline = time.Since(prev.lastHCAt) + prev.offlineDuration
							} else {

		if di.RootDisk {
			rootDiskCount++
		}
	}

	// Count offline disks as well to ensure consistent
	// reportability of offline drives on local setups.
	if len(disksInfo) == (rootDiskCount + offlineDisks.Sum()) {
		// Success.
		return onlineDisks, offlineDisks
	}

	// Root disk should be considered offline
	for i := range disksInfo {
		ep := disksInfo[i].Endpoint
		if disksInfo[i].RootDisk {

		go func(index int, c NetLocker) {
			defer wg.Done()

			if c == nil {
				ch <- refreshResult{offline: true}
				return
			}

			ctx, cancel := context.WithTimeout(ctx, ds.Timeouts.RefreshCall)
			defer cancel()

			refreshed, err := c.Refresh(ctx, args)
			if err != nil {
				ch <- refreshResult{offline: true}
				log("dsync: Unable to call Refresh failed with %s for %#v at %s\n", err, args, c)
			} else {