SQL Server Cluster Service Online Pending Status
The default restart settings in WSFC are such that a faulting resource is terminated and then retried once before being declared offline.

In this case: the cluster discovers the fault, calls for terminate and then attempts to re-online.  Storage Foundation for Windows detects that the Disk Group is not present and returns a status of Pending.  This creates a deadlock that lasts until either RHS.exe terminates (through hang protection); or the online pending timeout is reached.

So, recommend to change Pending timeout and deadlock timeout as per below link.

To change deadlock timeout(Values are in milliseconds)

(Get-ClusterResource “Resource Name”).DeadlockTimeout = 300000

To change pending timeout follow below steps:


In the Failover Cluster Management snap-in, if the cluster you want to configure is not displayed, in the console tree, right-click Failover Cluster Management, click Manage a Cluster, and select or specify the cluster you want.
If the console tree is collapsed, expand the tree under the cluster that you want to configure.
Expand Services and Applications.
Click the clustered service or application that you want to configure the pending timeout for.
In the center pane, right-click the resource for the service or application, click Properties, and then click the Policies tab.
Under Pending timeout, specify the length of time, in minutes and seconds, that the resource can take to change states between Online and Offline before the Cluster service puts the resource in the Failed state.


The default timeout value is 3 minutes. Change as per requirement.