The monitor checks latency for the disk read operation and throws an alert.
This alert indicates that the average time that it takes to read data from the disk has stayed greater than threshold during an interval.
Note: This monitor is disabled by default. Please use overrides to enable it when necessary.
The problem may be caused by a disk bottleneck or disk contention.
To resolve this error, do one or more of the following:
Determine if disk performance has degraded or workload has increased.
Evaluate SQL Server Storage Best practices.
Determine if storage for database files has been overcommitted e.g. shared storage in SAN or Virtual Machines.
SQL Server Best Practices Article (Disk Configuration Best Practices & Common Pitfalls)