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Elastic Compute Service:Disk event description

Last Updated:Mar 20, 2025

CloudLens for Elastic Block Storage (EBS) monitors and reports risk events when disk performance data exceeds certain thresholds or when snapshots for data backup are not created. Prompt event handling is crucial to maintain stable disk operation and ensure data security. This topic describes the event types CloudLens for EBS can report, provides detailed event descriptions, and offers handling recommendations for various events.

Event property description

Event property

Description

EventName

The name of the event.

ResourceId

The ID of the disk associated with the event.

ResourceType

The type of the resource associated with the event. Example: disk.

Description

The description of the event.

EventType

Event type:

  • Notification: an event that is triggered based on usage and can be immediately closed after the event is reported

  • Alert: an event that is triggered based on usage and must be manually closed

  • System exception: a critical event that is triggered by an underlying issue and affects disk usage

EventLevel

Event level:

  • Critical: critical

  • Warn: warning

  • Info: information

EventId

The event ID, which is unique for each resource.

EventStatus

Event status:

  • Active

  • Recovered

StartTime

The start time of the event.

EndTime

The end time of the event.

RecommendAction

The action recommended for the event. Valid values:

  • ModifyDiskSpec: changes the disk specification

  • CreateSnapshot: creates a snapshot for the disk

  • ResizeDisk: resizes the disk

  • AdjustProvision: changes the provisioned performance values of the disk

  • ModifyInstanceSpec: changes the instance type

RecommendParam

Parameter used in processing the event. For example, this parameter is set to a recommended provisioned value when the system processes a Cost Optimization event.

Note

You can query the properties of specific events on the Risk Events page in the console or by using the DescribeEvents API operation.

Event handling suggestions

The table below provides suggestions for handling different types of events.

Event name

Description

Trigger frequency

Event type

Event level

Handling suggestions

Determine whether the event is recovered

Data protection

You did not create snapshots for a disk for an extended period of time. In this case, you may be unable to restore the disk to the most recent state in the event of ransomware, which may cause data loss.

Every morning

Alert

Warn

Create a snapshot

After the disk is restored, a new event in the Recovered status is pushed for the disk the next morning. The historical Active events will not disappear.

Cost optimization

  • If the provisioned performance value such as 1,000 IOPS on a disk is higher than the actual workload such as 800 IOPS, you are charged for the higher performance level, which causes cost wastes.

  • If the provisioned performance value such as 1,000 IOPS on a disk is lower than the actual workload such as 1,200 IOPS, disk performance frequently bursts to process excess I/O requests, which increases the total cost.

You can change the provisioned values to balance performance and cost. For more information, see ESSD AutoPL disk.

Once a week

Alert

Info

After the disk is restored, no events of the same type are pushed.

Disk I/O Hang

An I/O hang occurred when the operating system became unstable or experienced downtime due to the excessively high read/write I/O latency of file systems on a disk.

Real time

SystemException

Critical

View the performance metrics of disks to identify the cause. For more information, see View disk monitoring information. For information about how to detect I/O hangs on Alibaba Cloud Linux operating systems, see Detect file system and block layer I/O hangs.

After the disk is restored, a new event in the Recovered status is pushed for the disk. The historical Active events will not disappear.

Specification mismatch between the instance and disks

The total specifications of disks on an instance exceed the upper limit supported by the instance type. The maximum disk performance may be limited by the instance type.

For example, if an ECS instance has a maximum IOPS of 60,000 and a disk that has a maximum IOPS of 100,000 is attached to the instance, the performance of the disk is limited by the instance type.

From 12:00 to 15:00 every day

Alert

Warn

When the total performance of disks on an instance exceeds the performance upper limit supported by the instance type, issues such as slow data processing and long response latency may occur.

We recommend that you change the instance type based on your business requirements. For more information, see Upgrade the specifications of subscription instances and Change the specifications of pay-as-you-go instances.

After the disk is restored, no events of the same type are pushed.

The IOPS of your instance reaches the upper limit

The total number of IOPS of disks attached to an instance reached the upper limit for the instance.

For example, the maximum IOPS of an ECS instance is 60,000 and two disks areattached to the instance. The IOPS of a disk is 10,000 and the IOPS of the other disk is 51,000. The total real-time IOPS of the disks on the instance reaches the maximum IOPS of the instance.

Within 5 minutes after the event is triggered

Note

The time is accurate to 5 minutes, and latency is measured in minutes.

Notification

Warn

An event in the Recovered status is reported when the event is triggered to remind you of these issues with the current disk. This does not involve whether the event is recovered.

The BPS of your instance reaches the upper limit

The total bytes per second (BPS) of disks on your instance reached the upper limit for the instance.

For example, the maximum BPS of an ECS instance is 150 MB/s, and two disks are attached to the instance. The BPS of a disk is 100 MB/s, and the BPS of the other disk is 60 MB/s. In this case, the total real-time BPS (160 MB/s) of the disks exceeds the maximum BPS for the instance.

Notification

Warn

IOPS of a disk reached maximum IOPS per instance

The IOPS of your disk reached the upper limit for the instance.

For example, an ECS instance has a maximum IOPS of 60,000, several disks are attached to the instance, and one disk has the IOPS of 70,000. In this case, the real-time IOPS of the disks exceeds the maximum IOPS for the instance.

Notification

Warn

BPS of a disk reached maximum BPS per instance

The BPS of your disk reached the upper limit for the instance.

For example, the maximum BPS of an ECS instance is 150 MB/s, several disks are attached to the instance, and the BPS of one disk is 160 MB/s. In this case, the real-time BPS of the disks exceeds the upper limit of the BPS for the instance.

Notification

Warn

IOPS of a disk reached maximum IOPS per disk

The IOPS of your disk reached the upper limit for the disk.

Notification

Warn

Issues such as slow data processing and high response latency may occur on the disk. For performance metrics of various types of disks, see Block storage performance.

  • We recommend that you view the performance metrics of the disk. For more information, see View disk monitoring information.

  • We recommend that you reduce the read/write frequency of the disk or upgrade the disk to a disk category that provides higher performance. For more information, see Change the disk category.

  • You can also extend the disk capacity to improve the performance of the disk. For more information, see Disk scale-out.

BPS of a disk reached maximum BPS per disk

The BPS of your disk reached the upper limit for the disk.

Notification

Warn

Non-4K-aligned read/write operation

Read/write operations on your disk are not 4K-aligned, which may affect disk I/O performance.

Note

If read/write operations in partitions on the disk are not 4K-aligned, the disk may perform a read-modify-write operation across two 4K sectors. As a result, a read/write operation may involve multiple I/O operations, which degrades the performance of the disk.

Reported at 12:00 every day

Notification

Info

For more information, see I/O performance optimization: Improve I/O performance by using 4K alignment

Slow I/O detected on your disk

Your disk has slow I/O that lasts for 1 second or longer.

Real time

Notification

Warn

Slow I/O may affect applications that depend on disk performance, such as causing website loading delays. We recommend that you check whether your business is affected at the earliest opportunity.

Disk I/O burst

Disk I/O Burst occurred on your disk, which may incur performance burst fees.

For more information, see ESSD AutoPL disk.

Every 1 hour

Notification

Info

We recommend that you check whether burst I/O of the disk meets your business expectations.

Disk performance burst fee cap

Your disk experienced a performance burst, and the total burst I/O triggered the performance burst fee cap rule

Every 1 hour, the total burst I/O of the past hour is calculated to determine whether the fee cap rule is triggered

Notification

Info

Although the performance burst fee cap rule can help you save on burst fees, we recommend that you check whether burst I/O meets actual needs to avoid unexpected business demands for burst I/O.