Performance (Host I/O)

Overview

This function displays the performance information of the volumes for Host I/O.

Note

  • Performance information is obtained when performance monitoring is operated from Web GUI, CLI, or any other monitoring software. Refer to the [Start/Stop Performance Monitoring] function for details on how to start performance monitoring with Web GUI.

  • The interval for acquiring performance information can be specified when starting the monitoring. When using Web GUI, the default interval is 30 seconds.

  • The average performance values during the specified interval are displayed.

  • When the performance monitoring function is stopped, "0" is displayed as the performance information.

  • This function displays the parameter that is set in the [Modify Cache Parameters] function.

  • This function displays the parameter (ALUA) that is set in the [Set ALUA] function.

  • In this manual, "volumes" include "External Volumes" if differentiation is not specifically required.

Display Contents

In this screen, the performance information of the volumes for Host I/O is displayed. When the performance monitoring function is stopped, "0" is displayed as the performance information.

Volume List

Item Description

No.

The volume number is displayed.

Click this item to display the [Volume Detail] screen ([Basic] tab).

Name

The volume name is displayed.

Click this item to display the [Volume Detail] screen ([Basic] tab).

Type

The volume type is displayed.

Standard

WSV

TPV

FTV

SDV

SDPV

Temporary

Usage

The usage of the volume is displayed.

Refer to Usage of Volumes for details.

Read IOPS

The number of reads per second is displayed.

A "-" (hyphen) is displayed for the Data Container Volume.

Write IOPS

The number of writes per second is displayed.

A "-" (hyphen) is displayed for the Data Container Volume.

Read Throughput

The amount of transferred data that is read per second is displayed.

A "-" (hyphen) is displayed for the Data Container Volume.

Write Throughput

The amount of transferred data that is written per second is displayed.

A "-" (hyphen) is displayed for the Data Container Volume.

Data Compression Rate

The compression rate (1 to 100 %) of the data that is written to the Deduplication/Compression Volume from the host is displayed.

A "-" (hyphen) is displayed for a volume other than the Deduplication/Compression Volume.

This item is displayed only when the Deduplication/Compression function is enabled.

Note

  • The compression rate of the data that is written when monitoring the performance information is displayed. Note that this value does not indicate the compression rate for the volume capacity.

Unaligned I/O Rate

The percentage (1 to 100 %) of data unsuited for the basic data size of the compression process among the data read/written from the host to the Deduplication/Compression Volume is displayed.

A "-" (hyphen) is displayed for a volume other than the Deduplication/Compression Volume.

This item is displayed only when the Deduplication/Compression function is enabled.

Caution

  • If the Unaligned I/O rate is high, the relevant volume performance may be greatly influenced by the Deduplication/Compression process. Disabling both Deduplication and Compression for the relevant volume may improve the performance. Select "Disable" for Deduplication and Compression and then migrate from the Deduplication/Compression Volume to the TPV. Refer to the [Start RAID Migration] function for details.

Read Response Time

The average read response time per host I/O is displayed.

A "-" (hyphen) is displayed for the Data Container Volume.

Write Response Time

The average write response time per host I/O is displayed.

A "-" (hyphen) is displayed for the Data Container Volume.

Read Processing Time

The average read processing time per host I/O is displayed.

A "-" (hyphen) is displayed for the Data Container Volume.

Write Processing Time

The average write processing time per host I/O is displayed.

A "-" (hyphen) is displayed for the Data Container Volume.

Read Cache Hit Rate

The cache hit rate (0 to 100 %) (for read) is displayed.

A "-" (hyphen) is displayed for the Data Container Volume.

Write Cache Hit Rate

The cache hit rate (0 to 100 %) (for write) is displayed.

A "-" (hyphen) is displayed for the Data Container Volume.

Prefetch Cache Hit Rate

The cache hit rate (0 to 100 %) (for prefetch) is displayed.

A "-" (hyphen) is displayed for the Data Container Volume.

Extreme Cache Cache Hit Rate

The cache hit rate (0 to 100 %) of Extreme Cache for read I/O is displayed.

This item is displayed if Extreme Cache Pool of the storage system is enabled.

A "-" (hyphen) is usually displayed for the following volumes:

  • Extreme Cache Pool for the relevant volume is disabled

  • Volume type is "SDV" or "SDPV"

  • Volumes that are created in a RAID group or a TPP configured with motorless drives (such as SSDs or NVMe SSDs)

  • Data Container Volumes

  • ODX Buffer volumes

Note

  • Enabling or disabling Extreme Cache Pool for each volume can be performed with Web GUI or CLI. Use the [Modify Cache Parameters] function to change the setting from Web GUI.

Cache Page Capacity

The cache page capacity is displayed.

When the cache page capacity is "-" (hyphen), there is no limit for the cache capacity.

A "-" (hyphen) is displayed when the volume type is "TPV", "FTV", or "WSV".

Note that a "-" (hyphen) is displayed for a "Standard" type volume that is concatenated by the LUN Concatenation function.

PL

The prefetch limit is displayed.

If PL is "0", prefetch is not performed.

FP

The selected usage for the Force Prefetch Mode, which performs forcible prefetching for cache, is displayed.

  • ON:

    Perform prefetch even if the sequential characteristics of the data access is not detected.

  • OFF:

    Perform prefetch only when the sequential characteristics of the data access is detected.

MWC

The value of the Multi Writeback Count is displayed.

A "-" (hyphen) is displayed when the volume type is "TPV" or "FTV".

Note that a "-" (hyphen) is displayed for a "Standard" type volume that is concatenated by the LUN Concatenation function.

PSDC

The number of times that sequentiality of data access (Read I/O) is detected (value of the Prefetch Sequential Detect Count) is displayed. If any sequential data is accessed for the number of times specified for PSDC, such access is determined as sequential access and prefetch is performed.

SDDC

The number of times that sequentiality of data access (Write I/O) is detected (value of the Sequential Dirty Detect Count) is displayed. If any sequential data is accessed for the number of times specified for SDDC, such access is determined as sequential access and prefetch is performed.

SS

The value of the parameter (Sequential Slope) to determine the sequentiality of data access (Read I/O) is displayed. If the difference in addresses between the end LBA of the previous I/O and the start LBA of the current I/O is within (SS setting + 1), it is determined as sequential data.

SDS

The value of the parameter (Sequential Dirty Slope) to determine sequential data access (Write I/O) is displayed. If the difference in addresses between the end LBA of the previous I/O and the start LBA of the current I/O is within (SDS setting + 1), it is determined as sequential data.

SPMC

The value of the parameter (Sequential Parallel Multi I/O Count) to determine the sequentiality of data access (Read I/O and Write I/O) is displayed. If the difference in addresses between the start address of the previous I/O and the start address of the received I/O is within (I/O size × Specified value), it is determined as sequential data.

ALUA

The set state for Asymmetric Logical Unit Access (ALUA) is displayed. A "-" (hyphen) is displayed for any volumes that cannot be mapped (*1).

  • Follow Host Response

    Use the same "Asymmetric / Symmetric Logical Unit Access" setting as the host response for the host group or the host.

  • ACTIVE / ACTIVE

    All of the paths to the volume are regarded as being recommended paths. The use of a multipath driver determines which paths are used.

  • ACTIVE-ACTIVE / PREFERRED_PATH

    There are recommended paths and non-recommended paths for each volume. By using a CA port in the Controlling CM of a RAID group in which the volume belongs for the recommended paths (other ports are regarded as non-recommended paths), data migration between CMs (cross access) can be reduced.

*1  :  The following volumes cannot be mapped.

  • "SDPV" or "Temporary" type volumes

  • ODX Buffer volumes

  • "Usage" is "System"

[Volume Detail] Screen ([Basic] Tab)

Click the [Performance (Host I/O)] tab to display the detailed information.

[Performance (Host I/O)] Screen

The volume number, volume name, type, and usage are displayed.

Item Description

Read IOPS

The number of reads per second is displayed.

Write IOPS

The number of writes per second is displayed.

Read Throughput

The amount of transferred data that is read per second is displayed.

Write Throughput

The amount of transferred data that is written per second is displayed.

Data Compression Rate

The compression rate (1 to 100 %) of the data that is written to the Deduplication/Compression Volume from the host is displayed.

A "-" (hyphen) is displayed for a volume other than the Deduplication/Compression Volume.

This item is displayed only when the Deduplication/Compression function is enabled.

Unaligned I/O Rate

The percentage (1 to 100 %) of data unsuited for the basic data size of the compression process among the data written from the host to the Deduplication/Compression Volume is displayed.

A "-" (hyphen) is displayed for a volume other than the Deduplication/Compression Volume.

This item is displayed only when the Deduplication/Compression function is enabled.

Read Response Time

The average read response time per host I/O is displayed.

Write Response Time

The average write response time per host I/O is displayed.

Read Processing Time

The average read processing time per host I/O is displayed.

Write Processing Time

The average write processing time per host I/O is displayed.

Read Cache Hit Rate

The cache hit rate (0 to 100 %) (for read) is displayed.

Write Cache Hit Rate

The cache hit rate (0 to 100 %) (for write) is displayed.

Prefetch Cache Hit Rate

The cache hit rate (0 to 100 %) (for prefetch) is displayed.

Extreme Cache Cache Hit Rate

The cache hit rate (0 to 100 %) of Extreme Cache for read I/O is displayed.

This item is displayed if Extreme Cache Pool of the storage system is enabled.

A "-" (hyphen) is usually displayed for the following volumes:

  • Extreme Cache Pool for the relevant volume is disabled

  • Volume type is "SDV" or "SDPV"

  • Volumes that are created in a RAID group or a TPP configured with motorless drives (such as SSDs or NVMe SSDs)

  • Data Container Volumes

  • ODX Buffer volumes

Cache Page Capacity

The cache page capacity is displayed.

When the cache page capacity is "-" (hyphen), there is no limit for the cache capacity.

A "-" (hyphen) is displayed when the volume type is "TPV", "FTV", or "WSV".

Note that a "-" (hyphen) is displayed for a "Standard" type volume that is concatenated by the LUN Concatenation function.

PL

The prefetch limit is displayed.

FP

The selected usage for the Force Prefetch Mode, which performs forcible prefetching for cache, is displayed.

MWC

The value of the Multi Writeback Count is displayed.

A "-" (hyphen) is displayed when the volume type is "TPV" or "FTV".

Note that a "-" (hyphen) is displayed for a "Standard" type volume that is concatenated by the LUN Concatenation function.

PSDC

The number of times that sequential data access is detected (value of the Prefetch Sequential Detect Count) is displayed.

SDDC

The number of times that sequentiality of data access (Write I/O) is detected (value of the Sequential Dirty Detect Count) is displayed.

SS

The value of the parameter (Sequential Slope) to determine the sequentiality of data access (Read I/O) is displayed.

SDS

The value of the parameter (Sequential Dirty Slope) to determine sequential data access (Write I/O) is displayed.

SPMC

The value of the parameter (Sequential Parallel Multi I/O Count) to determine the sequentiality of data access (Read I/O and Write I/O) is displayed.

ALUA

The set state for Asymmetric Logical Unit Access (ALUA) is displayed. A "-" (hyphen) is displayed for any volumes that cannot be mapped.

Follow Host Response

ACTIVE / ACTIVE

ACTIVE-ACTIVE / PREFERRED_PATH