IO traffic analysis

Limitations

• Region limitations

  This feature is available only in the Chinese mainland and China (Hong Kong) regions.

• Operating system limitations

  Architecture	Operating system
  x86 architecture	Rocky Linux 9.5 Rocky Linux 9.1 Ubuntu 20.04 Alibaba Cloud Linux 3 Container-Optimized Edition Rocky Linux 8.8 Ubuntu 22.04 Alibaba Cloud Linux 3 Pro Alibaba Cloud Linux 2/3 CentOS 7.6 or later, or CentOS 8 Anolis OS 7/8 Ubuntu 24.04
  ARM architecture	Alibaba Cloud Linux 3 Pro Alibaba Cloud Linux 3

Prerequisites

• If you use a RAM user, ensure that the Alibaba Cloud account (main account) has granted the AliyunECSReadOnlyAccess and AliyunSysomFullAccess system policies to the RAM user.

• Console access is enabled.

  When you log on to the Operating System Console for the first time, click Activate Service to activate the service.

Procedure

1. Go to the Operating System Console.

2. In the left-side navigation pane, click System Diagnosis.

3. In the upper-left corner of the page, select the region where your target instance is located.

   

4. In the Diagnosis Type list, select Storage Diagnosis. From the Diagnosis Item list, select IO traffic analysis. Configure the parameters and click Run Diagnosis.

   Note

   If SysOM is not installed, the system automatically installs it on the target ECS instance after you click Run Diagnosis and then starts the diagnosis.

   This table describes the parameters for the diagnosis.

   Parameter	Description	Required
   instance ID	The ID of the target ECS instance.	Yes
   Diagnosis Duration	The duration of the diagnosis. Default: 15 seconds.	Yes
   target disk	The name of the disk to diagnose, such assda.	Optional. If you do not specify this parameter, the diagnosis runs on all disks.

5. In the Diagnosis Records section, click View Report.

   

Diagnostic report

A diagnostic report contains all information from a single diagnosis.

• Basic Information

  The Basic Information section summarizes the diagnosis with key details, including the instance ID (which serves as the resource ID), diagnosis item, diagnostic report ID, and diagnosis start time.

• Diagnosis Conclusion

  • If the IO traffic is within the normal range, the report displays the current I/O performance metrics.

  • If abnormal IO traffic is detected, the report displays the cause of the anomaly.

• Diagnosis Suggestion

  This section provides recommended actions based on the diagnosis results.

• Diagnosis Details

  The Diagnosis Details section has four parts: Cause Analysis, Disk-Level I/O Traffic List, Process-Level I/O Traffic List, and Process I/O Block Size Distribution.

  • Cause Analysis

    The Cause Analysis section displays the I/O traffic generated by processes that access the disk. It typically shows the IOPS and IO throughput for a specific process that accesses a specific disk and identifies the target file being accessed.

  • Disk-level I/O Traffic List

    This section shows the disk I/O traffic statistics collected during the diagnosis and explains its key fields.

    

    • Disk/Partition Name: The name of the diagnosed disk or partition.

    • Number of Merged Read I/Os: The number of merged read operations during the diagnosis.

    • Number of Merged Write I/Os: The number of merged write operations during the diagnosis.

    • Read I/O throughput: The read IO throughput during the diagnosis.

    • Write I/O throughput: The write IO throughput during the diagnosis.

    • Average IO latency: The average time for an I/O operation to complete.

    • Average read IO latency: The average time required for each read operation.

    • Average write IO latency: The average time required for each write operation.

    • IO utilization (percentage): The percentage of time the disk was busy processing I/O requests.

  • Process-level I/O Traffic List

    This section displays the process-level I/O traffic during the diagnosis and explains the key fields.

    • Process Name: The name of the process. 

    • Parent Process ID: Process ID: The process ID.

    • Read I/O count: The read IOPS contributed by the process.

    • Write IOPS: The write iops contributed by the process.

    • Read I/O throughput: Read bps contributed by the process.

    • Write I/O throughput: The write bps contributed by the process.

    • Disk Cache Flush Count: The number of flush IO operations generated by the process.

    • Disk/Partition Name: The target disk that consumed the I/O.

    • File Name: The source file that generated the I/O.

    This feature allows you to trace the source of I/O that the kworker process uses to flush dirty pages. As a result, sub-items are displayed under the kworker process, which you can expand to identify the actual process that generates dirty pages by writing to buffer I/O.

    

  • Process I/O Block Size Distribution

    This section shows the distribution of I/O block sizes that processes submitted to the OS block layer during the diagnosis and explains the key fields.

    

    • Process Name: The name of the process. 

    • Parent Process ID: Process ID: Process ID information

    • nK write I/O percentage: The percentage of I/O operations with a size of nK.

    • Percentage of Write I/Os Larger Than 512 KB: The percentage of write operations with a block size larger than 512 KB.