You can view the monitoring data of disks, such as IOPS and throughput, in the Elastic Compute Service (ECS) or CloudMonitor console. You can troubleshoot issues and determine whether to extend or upgrade disks based on the monitoring data of the disks. This topic describes how to view the monitoring data of disks in the ECS and CloudMonitor consoles.
Background information
Disk performance is measured by using the following metrics:
IOPS: measures the number of read and write operations that an Elastic Block Storage (EBS) device can process per second. High IOPS is essential for transaction-intensive applications.
Throughput: measures the amount of data transferred per second. Unit: MB/s. High throughput is essential for applications that require a large number of sequential read and write operations.
Latency: measures the amount of time that is required for an EBS device to process an I/O request. Unit: seconds, milliseconds, or microseconds. High latency may cause performance to degrade or lead to errors in applications that require low latency.
For information about the performance of different disk categories, see Block storage performance.
View the IOPS, throughput, and latency of a disk
You can view the IOPS, throughput, and latency of a disk on the Disks page in the ECS console.
Log on to the ECS console.
In the left-side navigation pane, choose .
In the upper-left corner of the top navigation bar, select a region.
Find the disk whose monitoring data you want to view and click the disk ID to go to the Basic Information tab of the disk details page.
Click the Monitoring tab.
In the Time Range section, click the
icon to specify the beginning and end of the time range to query. 
View the IOPS, throughput, and latency of the disk. You can move the pointer over a point in time in the charts to view metric information.
If monitoring data indicates that disk performance is bottlenecked, you can optimize your business applications or upgrade the disk. For information about how to upgrade a disk, see Change the category of a disk.
View other monitoring data of a disk
You can view monitoring data, such as the disk usage, inode usage, and number of bytes, in the CloudMonitor console and configure alert rules based on actual scenarios. The following table describes the metrics of disks. For more information, see Metrics.
Metric | Description | Unit | MetricName | Dimensions | Statistics |
Host.diskusage.used | The disk space in use. | Byte | diskusage_used | userId, instanceId, and device | Maximum, Minimum, and Average |
Host.diskusage.utilization | The disk usage. | % | diskusage_utilization | userId, instanceId, and device | Maximum, Minimum, and Average |
Host.diskusage.free | The size of available disk space for regular users and superusers. | Byte | diskusage_free | userId, instanceId, and device | Maximum, Minimum, and Average |
(Agent)disk.usage.avail_device | The size of available disk space for regular users. | Byte | diskusage_avail | userId, instanceId, and device | Maximum, Minimum, and Average |
Host.diskusage.total | The size of the total disk space. | Byte | diskusage_total | userId, instanceId, and device | Maximum, Minimum, and Average |
(Agent)disk.read.bps_device | The number of bytes that are read from the disk per second. | Byte/s | disk_readbytes | userId, instanceId, and device | Maximum, Minimum, and Average |
(Agent)disk.write.bps_device | The number of bytes that are written to the disk per second. | Byte/s | disk_writebytes | userId, instanceId, and device | Maximum, Minimum, and Average |
(Agent)disk.read.iops_device | The number of read requests that the disk receives per second. | Requests/s | disk_readiops | userId, instanceId, and device | Maximum, Minimum, and Average |
(Agent)disk.write.iops_device | The number of write requests that the disk receives per second. | Requests/s | disk_writeiops | userId, instanceId, and device | Maximum, Minimum, and Average |
The following steps describe how to view the monitoring data of a disk and how to configure alert rules for the disk in the CloudMonitor console:
Log on to the CloudMonitor console.
Install the CloudMonitor agent.
For more information, see Install and uninstall the CloudMonitor agent for C++.
View the monitoring data of a disk.
In the left-side navigation pane, click Host Monitoring.
On the Host Monitoring page, find the ECS instance whose monitoring data you want to view and click the name of the instance in the Host Name/ID column.
On the Host Monitoring Details page, click the OS Monitoring tab.
In the Disk Metric section, view the monitoring data of a disk that is attached to the instance.
(Optional) Configure alert rules for the disk.
For more information, see Alert service.
NoteYou can configure alert rules based on your business requirements. If the values of disk metrics meet alert conditions, alerts are triggered and CloudMonitor sends alert notifications to help you identify and handle exceptions at the earliest opportunity.
If monitoring data indicates that disk performance is bottlenecked, you can optimize your business applications or upgrade the disk. For information about how to upgrade a disk, see Change the category of a disk.
If the amount of available storage space on the disk is low, delete data that is no longer needed to free up space or extend the disk. For information about how to extend a disk, see Overview.