Deployment Best Practices : Microsoft and ESX iSCSI initiator timeouts
  
Microsoft and ESX iSCSI initiator timeouts
By default, the Microsoft iSCSI Initiator LinkDownTime timeout value is set to 15 seconds and the MaxRequestHoldTime timeout value is also 15 seconds. These timeout values determine how much time the initiator holds a request before reporting an iSCSI connection error. You can increase these values to accommodate longer outages, such as an Edge failover event or a power cycle in the case of a single appliance.
If MPIO is installed in the Microsoft iSCSI Initiator, the LinkDownTime value is used. If MPIO is not installed, MaxRequestHoldTime is used instead.
If you are using Edge in an HA configuration and MPIO is configured in the Microsoft iSCSI Initiator, change the LinkDownTime timeout value to 60 seconds to allow the failover to complete.
By default, the VMware ESX iSCSI Initiator DefaultTimeToWait timeout is set to 2 seconds. This amount of time is the minimum to wait before attempting an explicit or implicit logout or active iSCSI task reassignment after an unexpected connection termination or a connection reset. You can increase this value to accommodate longer outages, such as an Edge failover event or a power cycle in case of a single appliance.
If you are using Edge in an HA configuration, change the DefaultTimeToWait timeout value to 60 seconds to allow the failover to complete.