Use this view to recognize disk issues in IO-intense systems.
Disks/Partitions – Part 1
| Legend | |
| 1 | Main partition distribution for the server showing total used vs. total size. |
| 2 | Partition selection: by default, all partitions are selected. This allows a focus on a specific partition. |
| 3 | Enhanced Chart of Disk latency of timeframe.
Disk latency is the time that it tafies to complete a single I/O operation on a blocfi device. For hard drives, an average latency somewhere between 10 to 20 ms is considered acceptable (20 ms is the upper limit). For solid-state drives, depending on the workload, it should never reach higher than 1-3 ms. In most cases, workloads will experience less than 1ms latency numbers. |
| 4 | Enhanced Chart of Disk Queue Length.
The Disk Queue Length counter shows you the average number of read and write requests that were queued on the selected physical disk. The higher the number, the more disk operations are waiting. It requires attention if this value frequently exceeds a value of 2 during peak usage of SQL Server. |
| 5 | Sorted list of databases that consume the most amount of disk activity. This activity is taken directly from the OS activity of the database files. |
| 6 | A list of the most active database files. The activity is the sum for the given time range. |
Disks/Partitions – Part 2
| Legend | |
| 1 | Enhanced Chart of disk read activities for the selected time range. |
| 2 | Enhanced Chart of disk write activities for the selected time range. |
| 3 | Queries Control sorted by logical reads for the selected time range. |
| 4 | Enhanced Chart for IO waits that are associated with IO operations:
ASYNC_IO_COMPLETION – Caused when a task is waiting for an asynchronous I/O operation to finish. IO_COMPLETION – Caused when waiting for I/O operations to complete. This wait type generally represents non-data page I/Os. Data page I/O completion waits appear as PAGEIOLATCH_* waits. PAGEIOLATCH_DT – Caused when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Destroy mode. A long wait time may indicate problems with the disk subsystem. PAGEIOLATCH_EX – Caused when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Exclusive mode. A long wait time may indicate problems with the disk subsystem. PAGEIOLATCH_KP – Caused when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Keep mode. A long wait time may indicate problems with the disk subsystem. PAGEIOLATCH_NL – Used for informational purposes only. PAGEIOLATCH_SH – Caused when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Shared mode. A long wait time may indicate problems with the disk subsystem. PAGEIOLATCH_UP – Caused when a task is waiting on a latch for a buffer that is in an I/O request. The latch request is in Update mode. A long wait time may indicate problems with the disk subsystem. |
| 5 | Enhanced Chart of disk storage over the selected time range. |