hIOmon Software and Services

hIOmon SNIA SSSI WIOCP Metrics Definitions

This web page provides detailed information about the various types of automatically-summarized I/O operation performance metrics that were collected and exported by the Storage Networking Industry Association (SNIA) Solid State Storage Initiative (SSSI) “Workload I/O Capture Program (WIOCP)”.

 

Which hIOmon summary I/O operation performance metrics were exported

Each export file contains nearly 300 different summary I/O operation performance metrics.  These metrics include:

  • Name of the monitored device (or process name and associated process image file name in the case of the process summary export file)
  • Timestamp (month, date, hour, minute, second) when the metrics were prepared for offload to the hIOmon Manager service (so that they could then be exported/saved to the export file)
  • "Duration (i.e., the length of time in seconds during which the associated summary I/O operation performance metrics were collected by the hIOmon I/O Monitor)
  • Separately for both read and write I/O operations and as observed by the hIOmon I/O Monitor:

    -  Accumulated number of I/O operations
    -  Accumulated number of "Fast" I/O operations; that is, I/O operations that were successfully completed in less than one millisecond as observed by the hIOmon I/O Monitor either by explicit request for use of the "system file cache" (SystemCache Hits) or not (i.e., successfully completed in less than one millisecond but did not explicitly request the use of the "system file cache")
    -  Accumulated number of "System File Cache" I/O operations; that is, I/O operations that were successfully performed using the system file cache by explicit request as observed by the hIOmon I/O Monitor
    -  Accumulated number of System File Cache "miss" I/O operations; that is, I/O operations that were successfully performed using the system file cache by explicit request, but took one or more milliseconds to complete as observed by the hIOmon I/O Monitor.  Note that the "System Cache" I/O operation "hit" count can be derived by subtracting the "miss" count from the total System Cache I/O operation count (i.e., the "System File Cache" I/O operation count defined above); this derived "hit" count represents the number of I/O operations that were successfully performed using the system file cache by explicit request and which completed within less than one millisecond as observed by the hIOmon I/O Monitor.
    Maximum IOPS observed during the period (note that this reflects the actual number of I/O operations observed during the 10-minute summary period) 
    Average queue length observed during the period 
    Maximum queue length observed during the period 
    -  Accumulated total (in seconds) of the time durations associated with the I/O operations
    -  Minimum time duration (in seconds) for an observed I/O operation (i.e., minimum response time) during the period
    -  Maximum time duration (in seconds) for an observed I/O operation (i.e., maximum response time) during the period
    -  Accumulated total (in bytes) of data transferred by the I/O operations
    - Smallest data transfer size (in bytes) associated with an observed I/O operation (i.e., minimum data transfer size) during the period
    - Largest data transfer size (in bytes) associated with an observed I/O operation (i.e., maximum data transfer size) during the period
    Maximum MB/s observed during the period (note that this reflects the actual amount of data transferred in bytes by the I/O operations observed during the period)
    -  Accumulated number of I/O operations that represent a random access (i.e., the random access I/O count).  An I/O operation is considered to be a random access when the data transferred at its starting address is not contiguous to the address of the last data transferred by the preceding I/O operation of the same type.
    -  Accumulated total (in bytes) of data transferred by I/O operations that performed a random access (i.e., the random access data transferred amount)
    -  Accumulated number of I/O operations that represent a sequential access (i.e., the sequential access I/O count).  An I/O operation is considered to be a sequential access when the data transferred at its starting address is contiguous to the address of the last data transferred by the preceding I/O operation.
    -  Accumulated total (in bytes) of data transferred by I/O operations that performed a random access (i.e., the random access data transferred amount)
    -  Accumulated total (in bytes) of data transferred by I/O operations that performed a sequential access (i.e., the sequential access data transferred amount)
    -  Accumulated total (in bytes) of data transferred by I/O operations that were successfully performed using the system file cache by explicit request and which completed in less than one millisecond as observed by the hIOmon I/O Monitor (i.e., the system file cache hit data transferred amount)
    -  Accumulated total (in bytes) ) of data transferred by I/O operations that were successfully performed using the system file cache by explicit request, but which took one or more milliseconds to complete as observed by the hIOmon I/O Monitor (i.e., the system file cache miss data transferred amount)
    Idle time period count, which reflects the accumulated count of idle time intervals as observed by the hIOmon I/O Monitor for the respective type of I/O operation.  That is, the total number of separate time intervals within which there were neither monitored read I/O operations (in the case of the read summary metric) in process nor any monitored read I/O operations queued/pending.
    Idle time period range count 5, which reflects the accumulated count for the respective type of I/O operation of idle time intervals whose time length was 60 or more seconds as observed by the hIOmon I/O Monitor.
    Maximum Idle time period, which reflects the maximum idle time interval between monitored I/O operations of the respective type as observed by the hIOmon I/O Monitor.
    IOPS Range Counts, which reflect the accumulated count of one-second time intervals during which the hIOmon I/O Monitor observed an actual total number of completed I/O operations of the respective type within the particular "I/O Operations Per Second (IOPS) Range"; see the "Main Display" section of the help information for the hIOmon Disk I/O Ranger Display for additional information about the hIOmon "Performance Threshold Range Counts".
    MBS Range Counts, which reflect the accumulated count of one-second time intervals during which the hIOmon I/O Monitor observed an actual total number of data bytes transferred by I/O operations of the respective type within the particular "Megabytes Per Second (MBs) Range"
    Queue Depth (QD) Range Counts, which reflect the total number of times that the hIOmon I/O Monitor observed an actual Queue Depth/Length for the respective I/O operation type within the corresponding "Queue Depth Range"
    Response Time (RT) Range Counts, which reflect the total number of times that the hIOmon I/O Monitor observed an I/O operation of the respective type whose response time (i.e. the time duration between the start of an I/O operation and the completion of the I/O operation, which includes both the service time and the queue time) was within the corresponding "RT Range"
  • Average and maximum queue lengths for read and write I/O operations combined as observed during the period

  • Accumulated number of I/O operations (whether Read or Write) that represented overall random accesses (i.e. regardless of whether the preceding I/O operation was a read or a write I/O operation).

  • Accumulated number of file I/O operations (whether Read or Write) that represented overall sequential accesses (i.e. regardless of whether the preceding I/O operation was a read or a write I/O operation).

  • Accumulated total (in bytes) of data transferred by I/O operations that performed an overall random access

  • Accumulated total (in bytes) of data transferred by I/O operations that performed an overall sequential access

  • RW IOPS Range Counts, which reflect the accumulated count of one-second time intervals during which the hIOmon I/O Monitor observed an actual total combined number of completed read and write I/O operations within the particular "I/O Operations Per Second (IOPS) Range"

  • RW MBS Range Counts, which reflect the accumulated count of one-second time intervals during which the hIOmon I/O Monitor observed an actual total number of data bytes transferred by read and write I/O operations combined within the particular "Megabytes Per Second (MBs) Range"

  • RW Queue Depth (QD) Range Counts, which reflect the total number of times that the hIOmon I/O Monitor observed an actual Queue Depth/Length for the read and write I/O operations combined within the corresponding "Queue Depth Range"

  • Maximum file count, which reflects the overall maximum number of files for which the respective process directed a file I/O operation, which I/O operations were observed and monitored by the hIOmon I/O Monitor, and for which the hIOmon I/O Monitor had combined, summarized I/O operation performance metrics; note that this metric only applies to processes.

  • TRIM command metrics, such as the total number of successful Control I/O operations observed by the hIOmon I/O Monitor that specified a "Device Control" operation with a "TRIM" action request, the overall total amount of bytes requested to be trimmed by all TRIM requests combined, the maximum total number of bytes specified by a single TRIM request, etc.; note that these metrics only apply to physical volumes and physical devices.

  • Idle time total (i.e. accumulated total duration in seconds as observed by the hIOmon I/O Monitor in which there were neither I/O operations in process nor any I/O operations queued)

  • Statistics Time Duration Base (i.e. time duration in seconds since the hIOmon I/O Monitor first started accumulating the associated summary I/O operation performance metrics)

  • Filter Selection ID (An unique numeric identifier that denotes the Filter Selection that was in effect when the summary I/O operation performance metrics were collected by the hIOmon I/O Monitor; this ID is generated/updated by the hIOmon I/O Monitor each time that a Filter Selection is loaded/activated within the hIOmon I/O Monitor and can be used to distinguish between overall observation periods.)

In addition to the summary I/O operation performance metrics noted above, the export files will additionally include the following "Physical Device Extended Metrics" I/O operation performance metric types:

  • Separately for Physical Device read and write I/O operations and as observed by the hIOmon I/O Monitor:
    -  Accumulated number of I/O operations
    - Accumulated number of "Fast" I/O operations; that is, the number of Physical Device I/O operations observed by the hIOmon I/O Monitor that were successfully completed in less than one millisecond.
    -  Both the minimum and the maximum response times observed during the period
    -  Accumulated total (in seconds) of the time durations associated with the I/O operations
    -  Accumulated total (in bytes) of data transferred by the I/O operations
    -  Both the minimum and the maximum data transfer size (in bytes) associated with an observed I/O operation during the period
    -  Accumulated number of I/O operations that represent random access (i.e. the random access I/O count).  An I/O operation is considered to be a random access when the data transferred at its starting address is not contiguous to the address of the last data transferred by the preceding I/O operation of the respective type.
    -  Accumulated total (in bytes) of data transferred by I/O operations that performed a random access (i.e. the random access data transferred amount)
    -  Accumulated number of I/O operations that represent sequential access (i.e. the sequential access I/O count).  An I/O operation is considered to be a sequential access when the data transferred at its starting address is contiguous to the address of the last data transferred by the preceding I/O operation of the respective type.
    -  Accumulated total (in bytes) of data transferred by I/O operations that performed a sequential access (i.e. the sequential access data transferred amount)
    -  Average queue and maximum queue lengths observed during the period

  • Accumulated number of Physical Device I/O operations (whether Read or Write) that represented an overall random access to the Physical Device.

  • Accumulated number of Physical Device I/O operations (whether Read or Write) that represented an overall sequential access to the Physical Device.

  • Accumulated total (in bytes) of data transferred by I/O operations that performed an overall random access

  • Accumulated total (in bytes) of data transferred by I/O operations that performed an overall sequential access

  • Average and maximum queue lengths for read and write I/O operations combined as observed during the period

Please note that that the export files contain no Personally Identifiable Information.