Setup Subsystem Parameters

Overview

This function specifies the subsystem parameters.

Subsystem parameters are the information which controls the storage system operation when it is connected to hosts. The storage system operates according to the specified subsystem parameters, for all the hosts to be connected.

Caution

  • If a change to subsystem parameters is required, the recommended time is when the load is low in the storage system.

  • Some subsystem parameters may require rebooting of the server or the storage system after changes have been made. Refer to "Conditions for Changing Subsystem Parameters" for details.

Conditions for Changing Subsystem Parameters (Parameters Can Be Changed while Accessing the Host: , Not Available: - , Storage System Reboot Is Required: , Storage System Reboot Is Not Required: -)

Category Subsystem parameter Changing parameters while accessing the host Rebooting
Storage System Server
Setup Subsystem Parameters 1CM Write Through
- -
Highland Mode -
-
Thin Provisioning Allocation Mode
- -
Flexible Write Through
- -
Ignore CM-CM Communication Error
- -
Read Sequential
- -
Write Sequential
- -
Turbo Mode
- -
Writeback Limit Count
- -
Slow Format
- -
Setup Host Load Balance
- -
Reject INQUIRY from Unauthorized Host
-
Optimize for Advanced Format SSD
-
Setup Disk Drive Critical Disk Mode
- -
Disk Media Error Check
- -
Check BID after Write Command
- -
Checkcode Enforcement
- -
Reduce the Timeout Period for Nearline Disks
- -
Skip Retry when Failed to Access
- -
Early Isolate Drive when Read Error
- -
HDD Shield
- -
Copybackless
- -
Setup Read Compare Mode Read Compare Mode for Online Disks
- -
Read Compare LBAs for Online Disks
- -
Read Compare Mode for Nearline Disks
- -
Web GUI Settings Function to Add Host
- -
Session Time-out
- -
Use Cookies for Session Confirmation
- -
Deduplication/Compression Settings Data Compare when hash collision occurs
- -

User Privileges

Availability of Executions in the Default Role

Default role Availability of executions
Monitor  
Admin
StorageAdmin  
AccountAdmin  
SecurityAdmin  
Maintainer

Refer to "User Roles and Policies" for details on the policies and roles.

Display Contents

Display Critical System Mode

Item Description

Multipath CSM Order

Whether or not the storage system received the instruction to enable/disable the Critical System Mode (CSM) from the host is displayed.

  • -- (Not Received)

    The storage system has not received the instruction.

  • On (Received)

    The storage system received the instruction to enable the CSM.

  • Off (Received)

    The storage system received the instruction to disable the CSM.

This item is available when logged in using a user account with the "Maintenance Operation" policy.

Settings

Setup Subsystem Parameters

Item Description Setting values

1CM Write Through

Set whether to shift mode of the storage system from Write Back to Write Through if only 1CM is available in the storage system because of a CM error.

This item is available when logged in using a user account with the "Maintenance Operation" policy.

Enable

Disable (Default)

Highland Mode

Set this mode when the storage system is used at a high altitude (1800m or higher). Select whether to enable or disable the Highland mode.

When Highland mode is enabled, the fan is run at high speed to preserve the fan's cooling effect.

This item is available when logged in using a user account with the "Maintenance Operation" policy.

Enable

Disable (Default)

Thin Provisioning Allocation Mode

Select "TPP balancing" or "TPV balancing" for the allocation mode of Thin Provisioning.

This mode is applied only for Thin Provisioning pools. Note that this setting is not applied for pools that are created by the Flexible Tier (Automated Storage Tiering) function.

  • TPP balancing

    Physical area is allocated almost evenly from the RAID groups that configure a TPP. Allocation is performed in order of writing to the TPV.

    This is a conventional method.

  • TPV balancing

    Physical area is allocated almost evenly from the RAID groups that configure a TPP. Allocation is performed by distributing RAID groups evenly for each TPV.

(Example)

Three TPVs (TPV#0, TPV#1, and TPV#2) are registered in a single TPP.

A single TPP is configured with four RAID groups (RAID group#0, RAID group#1, RAID group#2, and RAID group#3).

  • TPP balancing

    Physical area is allocated in the following order regardless of the TPV in which the data is written.

    RAID group#0 → RAID group#1 → RAID group#2 → RAID group#3 → RAID group#0 → •••

  • TPV balancing

    When data is written in TPVs that are registered in the TPP, the physical area is allocated in the following order.

    TPV#0: RAID group#0 → RAID group#1 → RAID group#2 → RAID group#3 → RAID group#0 → •••

    TPV#1: RAID group#1 → RAID group #2 → RAID group#3 → RAID group#0 → RAID group#1 → •••

    TPV#2: RAID group#2 → RAID group#3 → RAID group#0 → RAID group#1 → RAID group#2 → •••

Caution

  • The "Thin Provisioning Allocation Mode" is available only when the Thin Provisioning function is enabled.

TPP balancing (Default)

TPV balancing

Flexible Write Through

Select whether to enable or disable the Flexible Write Through.

If "Enable" is selected, the cache action is changed only for specific conditions.

  • Enable

    For the Flexible Write Through target I/O, by performing a special Write Through action, data is written to the drive in high speed. Therefore, duplication of the cache memory and parity is not performed.

    By enabling this function in the ETERNUS AF S3 series, CPU load reduction can be expected.

    Sequential write performance may improve if I/O size tuning is available from the host (such as with High Performance Computing) for the other models.

  • Disable

    Changes the cache action according to the cache mode of the storage system.

Caution

  • Do not change the default setting for normal use.

  • If "Enable" is selected for storage systems other than the ETERNUS AF S3 series, performance for the host I/O may improve only if all of the following conditions are satisfied. The target is the Write I/O for "Standard (including concatenation volumes by means of LUN Concatenation)" and "WSV".

    • Sequential write

    • The I/O size from the host is an integral multiple of the basic size (stripe size) for each RAID level

      Refer to "Basic Size and MWC Input Condition for RAID Levels" for details.

    • If any of the following RAID level is used:

      • RAID5 (2D+1P - 8D+1P)

      • RAID6 (3D+2P - 8D+2P)

      • RAID6-FR

        • (3D+2P)x2+1HS

        • (4D+2P)x2+1HS

        • (6D+2P)x2+1HS

        • (5D+2P)x4+1HS

        • (8D+2P)x3+1HS

        • (4D+2P)x5+1HS

        • (3D+2P)x6+1HS

  • If "Enable" is selected for the ETERNUS AF S3 series, performance for the host I/O may improve if any of the following conditions are satisfied.

    • When the RAID level is "RAID0", "RAID1+0", or "RAID1"

      The Write I/O for "Standard (including concatenation volumes by means of LUN Concatenation)" and "WSV"

    • When the RAID level is "RAID5", "RAID5+0", "RAID6", or "RAID6-FR"

      The Write I/O for "Standard (including concatenation volumes by means of LUN Concatenation)" and "WSV" where the I/O size from the host is an integral multiple of the basic size (stripe size) for each RAID group

  • If the cache mode of the storage system is in "Write Through Mode", regardless of whether "Flexible Write Through" is set, all I/Os will be operated with the Write Through mode.

Note

  • The cache modes for the storage system are "Write Back Mode" and "Write Through Mode". Refer to the [System] function for details.

For the ETERNUS DX S5 series

Enable

Disable (Default)

For the ETERNUS AF S3 series

Enable (Default)

Disable

Ignore CM-CM Communication Error

When communication is to be continued even when an error occurs in the paths between the CMs, select "Enable". To suspend communication between the CMs, select "Disable".

This item is available when logged in using a user account with the "Maintenance Operation" policy.

  • Enable

    Communication between the CMs is not suppressed even when an error occurs in the paths between the CMs.

  • Disable

    Communication between the CMs is suppressed when an error occurs in the paths between the CMs.

    This is the normal mode that is used.

Caution

  • Do not change the default setting ("Disable") for normal use.

  • If "Enable" is selected, the following problems may occur.

    • Machine down

    • Blocked host path

    • Disabled CM

    • Performance reduction

  • Change this item only when an online update of the CM fails. Try performing offline CM maintenance by following the instructions of a maintenance engineer.

Enable

Disable (Default)

Read Sequential

Select whether to enable or disable detection of the sequentiality when reading the data.

This item is available when logged in using a user account with the "Maintenance Operation" policy.

Caution

  • "Read Sequential" is an exclusive parameter for performance monitoring. Do not change the setting after installing the storage system.

Enable (Default)

Disable

Write Sequential

Select whether to enable or disable detection of the sequentiality when writing the data.

This item is available when logged in using a user account with the "Maintenance Operation" policy.

Caution

  • "Write Sequential" is an exclusive parameter for performance monitoring. Do not change the setting after installing the storage system.

Enable (Default)

Disable

Turbo Mode

Select whether to enable or disable the Turbo Mode.

The Turbo Mode is a function to improve performance by using processors in the CMs with an operating frequency that is higher than the specified rated value. This function is also referred to as "Intel® Turbo Boost Technology".

This item is displayed for the storage system other than the ETERNUS DX60 S5.

  • Enable

    Enable the Turbo Mode.

  • Disable

    Disable the Turbo Mode.

Caution

  • Do not change the default setting for normal use.

For the ETERNUS DX100 S5/DX200 S5 and the ETERNUS DX8100 S4

Enable

Disable (Default)

For the ETERNUS DX500 S5/DX600 S5/DX900 S5, the ETERNUS DX8900 S4, and the ETERNUS AF150 S3/AF250 S3/AF650 S3

Enable (Default)

Disable

Writeback Limit Count

Specify the maximum limit for the Writeback Limit Count (WLC).

The WLC is the number of commands that are issued when writing data back to the drive. When specifying a larger WLC, data writeback speed is increased. However, resources are used for data writeback so I/O performance may be affected.

Caution

  • Do not change the default setting (512) for normal use.

For the ETERNUS DX60 S5:

128, 256, 512, 1024

For the ETERNUS DX100 S5/DX200 S5 and the ETERNUS AF150 S3/AF250 S3:

128, 256, 512, 1024, 2048

For the ETERNUS DX500 S5 and the ETERNUS DX8100 S4

128, 256, 512, 1024, 2048, 3072

For the ETERNUS DX600 S5/DX900 S5, the ETERNUS DX8900 S4, and the ETERNUS AF650 S3

128, 256, 512, 1024, 2048, 3072, 6144

Default: 512

Slow Format

Select whether to enable or disable the slow format.

If the format function for this storage system starts, the performance of the volumes in operation may be influenced more than when the format function is used in older storage systems. Select "Enable" to revert the speed of the format process to the speed for older storage systems. This may reduce the performance impact to volumes in operation.

Enable

Disable (Default)

Setup Host

Item Description Setting values

Load Balance

Select whether to enable or disable the load balance for the storage system.

The Load Balance function delays execution for newly received commands when the command execution time in the storage system exceeds the specific value. Select "Enable" to respond with the sense that is specified in the "Load Balance Response" field of the host response setting.

Caution

  • When connecting the storage system and HP-UX hosts, disable the Load Balance setting. If the Load Balance setting is enabled, incorrect logs may be recorded in the host.

  • Load balancing by Multipath Driver is operated regardless of whether the Load Balance setting of this function is enabled/disabled.

Enable (Default)

Disable

Reject INQUIRY from Unauthorized Host

Select whether to reject the "Inquiry" command from an unauthorized host. Select the "Enable" checkbox to reject.

When the "Inquiry" command is rejected, storage system returns an Affinity Error (5/25/81) for the "Inquiry" command from the unauthorized host. When the command is not rejected, the storage system responds normally.

Caution

  • When using the Veritas Volume Manager Dynamic Multipathing (VxVM DMP), select "Enable". When VxVM DMP is not used, the setting of this parameter does not affect the state of the storage system.

Enable

Disable (Default)

Optimize for Advanced Format SSD

Select whether to perform a 4K byte alignment access from the host (host access that is aligned to 4K byte) to the volumes in RAID groups or TPPs configured with SSDs or SSD SEDs. Select "Enable" to perform a 4K byte alignment access.

Enable (Default)

Disable

Setup Disk Drive

Item Description Setting values

Critical Disk Mode

Select whether or not to shorten the monitoring time of the disk access. Select the "Enable" checkbox to shorten the monitoring time.

This item is available when logged in using a user account with the "Maintenance Operation" policy.

Enable (Default)

Disable

Disk Media Error Check

Select the checking method of disk medium errors from "Mode 1" and "Mode 2".

This item is available when logged in using a user account with the "Maintenance Operation" policy.

Mode1 (Default)

Mode2

Check BID after Write Command

Select whether to enable or disable the Block ID (BID) check after responding to a write command.

This item is available when logged in using a user account with the "Maintenance Operation" policy.

Enable

Disable (Default)

Checkcode Enforcement

Select whether to enable or disable the Checkcode Enforcement mode.

  • Enable

    Error detection function in the storage system is enhanced.

    When data is duplicated, the check codes of all the data blocks are checked.

  • Disable

    Error detection in the storage system is performed with the normal procedure.

Caution

  • Do not change the default setting ("Enable") for normal use.

  • If "Disable" is selected, the detection performance when errors occur is reduced.

Enable (Default)

Disable

Reduce the Timeout Period for Nearline Disks

Select whether to enable or disable for the timeout period reduction of Nearline disks.

This item is available when logged in using a user account with the "Maintenance Operation" policy.

  • Enable

    This mode gives priority to I/O response.

    Adds error counts more frequently to disks for signs of failure that cause delays with host responses.

  • Disable

    This mode gives priority to internal retry processes for a disk when an error occurs.

    Errors that occur intermittently such as a medium error can be solved.

Caution

  • Do not change the default setting ("Disable") for normal use.

    This mode works when an error occurs in a Nearline disk. If a Nearline disk is in normal status, both modes have no effect on the I/O response.

    A disk is regarded as having failed when the error count exceeds the threshold.

    When "Enable" is selected, error counts are added frequently. In this case, a disk error may be detected even when a slight failure or an error that occurs intermittently is detected.

    When "Disable" is selected, the I/O response to a disk that shows signs of failure may be reduced on a temporary basis.

Enable

Disable (Default)

Skip Retry when Failed to Access

Select whether to skip or not skip retrying when drive access fails.

This item is available when logged in using a user account with the "Maintenance Operation" policy.

  • Enable

    This mode gives priority to recovering drive performance when drive access fails.

    This mode is available when the storage system has 1 CE, 1 CM, 1 CA, and no DEs.

  • Disable

    This mode gives priority to retry processes when drive access fails.

    This mode prevents a component from being disconnected by false-positive error detection.

Caution

  • Do not change the default setting ("Disable") for normal use.

  • If "Enable" is selected, retry processes are suppressed when drive access fails. If the storage system has DEs or 2 or more CMs, do not select "Enable".

Enable

Disable (Default)

Early Isolate Drive when Read Error

Select whether to give priority to isolate a drive in which a drive read error is detected.

This item is available when logged in using a user account with the "Maintenance Operation" policy.

  • Enable

    This mode gives priority to isolate a drive in which a drive read error is detected.

    This reduces the response delay when a drive error occurs.

  • Disable

    This mode gives priority to the internal retry process for a drive in which a drive read error is detected.

    Errors that occur intermittently such as a medium error can be solved.

Caution

  • Do not change the default setting ("Disable") for normal use.

    This mode is performed when a medium error is detected while the drives are being read. This mode is applied for Online and Nearline disks.

    A drive is regarded as having failed when the error count exceeds the threshold.

    When "Enable" is selected, error counts are added frequently. In this case, a drive error may be detected even when a slight failure or an error that occurs intermittently is detected.

    When "Disable" is selected, the I/O response to a drive that shows signs of failure may be reduced on a temporary basis.

Enable

Disable (Default)

HDD Shield

Select whether to enable or disable the protect (shield) function for the drive.

The HDD Shield function temporarily isolates (protects) a drive in which an error is detected from the storage system and performs a diagnosis. If the drive is diagnosed as being normal, the drive is reactivated in the storage system. However, if disk errors other than HDD Shield occur or the error count exceeds the threshold, the drive is not reactivated.

This item is available when logged in using a user account with the "Maintenance Operation" policy.

Caution

  • The target drives for HDD Shield are the drives that are registered in RAID groups or as hot spares. The HDD Shield function is not applied to any unused drives.

Enable (Default)

Disable

Copybackless

Select whether to enable or disable the Copybackless function.

The Copybackless function registers the rebuilding destination hot spare in the RAID group after rebuilding is complete instead of performing a copyback operation. The failed drive in the RAID group is changed to a hot spare after the rebuilding is complete. If the failed drive is replaced with a normal drive, the replacement drive can be used as a hot spare. After the redundant copy is complete, this function is performed in the same way as the rebuilding function. Both types of hot spares (Global Hot Spares and Dedicated Hot Spares) can be the target hot spares for this function.

The Copybackless function is performed when the following hot spares are selected.

Caution

  • If the Copybackless function is enabled, a normal drive that replaces the failed drive cannot return to the original RAID group configuration. This should be taken into consideration when determining whether to enable or disable the Copybackless function.

Note

  • The Copybackless function is not performed when the first drive fails in a "RAID6-FR" type RAID group. A high-speed rebuild is performed in a hot spare area within the RAID group, and when the failed drive is exchanged for a normal drive, copyback is performed. The Copybackless setting is applied when the second drive fails.

Enable (Default)

Disable

Setup Read Compare Mode

Item Description Setting values

Read Compare Mode for Online Disks

Set the interval for read and compare operations in the data disk (online disk).

When "0" is specified in this item, the read and compare operations are not performed.

This item is available when logged in using a user account with the "Maintenance Operation" policy.

When the host requests data writing, the storage system reads and/or compares the data in the specified interval.

If an "Error" is detected during the reading/comparing process, the error is processed in the same way as when detecting a normal disk error.

Caution

  • Do not change this setting unless a maintenance engineer instructs otherwise.

0 - 255

16 (Default)

Read Compare LBAs for Online Disks

Set whether or not to compare the written volumes to all the Logical Block Addresses (LBAs) in the read and compare operations in data disks (online disks).

This item is available when logged in using a user account with the "Maintenance Operation" policy.

Caution

  • Do not change this setting unless a maintenance engineer instructs otherwise.

Compare all LBAs (Default)

Compare only initial LBA

Read Compare Mode for Nearline Disks

Set the interval for read and compare operations in the data disk (Nearline disk).

When "0" is specified in this item, the read and compare operations are not performed.

This item is available when logged in using a user account with the "Maintenance Operation" policy.

When the host requests data writing, the storage system reads and/or compares the data in the specified interval.

If an "Error" is detected during the reading/comparing process, the error is processed in the same way as when detecting a normal disk error.

Caution

  • Do not change this setting unless a maintenance engineer instructs otherwise.

0 - 255

16 (Default)

Web GUI Settings

Item Description Setting values

Function to Add Host

Select which function for adding hosts is to be used.

  • Use "Add Host Group"

    Create a host group and register the hosts as members. When the "Use "Add Host Group"" checkbox is selected, the actions for creating host groups are displayed.

  • Use "Add Host"

    Register hosts without creating host groups. When the "Use "Add Host"" checkbox is selected, the actions for adding hosts are displayed.

Caution

  • Selecting either "Use "Add Host Group"" or "Use "Add Host"" is recommended. If both of these checkboxes are not selected, the [Set] button cannot be clicked.

Note

  • Select "Use "Add Host"" only when using the previous procedure for registering hosts as the older storage systems (such as ETERNUS DX410/DX440 and ETERNUS DX8100/DX8400/DX8700). This checkbox is not selected by default. Both checkboxes can be selected at the same time.

Selected: Select

Cleared: Not select

Default:

Use "Add Host Group": selected

Use "Add Host": cleared
Session Time-out

Specify the time (in minutes) before Web GUI is automatically logged out.

The changed session timeout is applied for the Web GUI operations that are performed after this item is changed.

5 - 60

60 (Default)
Use Cookies for Session Confirmation

Select whether to use Cookies for session confirmations when accessing the storage system from Web GUI.

  • Enable

    In addition to a conventional session confirmation, perform a session confirmation using Cookies.

  • Disable

    Perform a conventional session confirmation.

Caution
  • For improved security over the conventional method for Web GUI access, select "Enable". If "Enable" is selected for this item, session confirmations using cookies are performed not only for users who log in to Web GUI after this parameter is changed, but also for users who are already logged in. If an authentication error occurs, an error message is displayed and the login state is lost.

Enable

Disable

Default:

  • When the storage system is newly shipped

    Enable

  • When the existing controller firmware is updated to V11L50 or later

    Disable

Deduplication/Compression Settings

Item Description Setting values

Data Compare when hash collision occurs

Select whether to compare the entire size of the data if the same hash value is detected when using the Deduplication/Compression function.

"Hash collision" indicates that the same hash value is generated from different data. By selecting "Enable" for this setting, if the hash value matches, the entire size of the data is compared with the existing data to determine whether it is duplicated.

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

Caution

  • Do not change the default setting ("Disable") for normal use.

  • Delete all the Deduplication/Compression Volumes in the storage system in advance. If Deduplication/Compression Volumes exist in the storage system, the current setting cannot be changed.

  • If "Enable" is selected, the performance is reduced.

Enable

Disable (Default)

Operating Procedures

  1. Click [Setup Subsystem Parameters] in [Action].

  2. Specify the parameters, and click the [Set] button.

    → A confirmation screen appears.

  3. Click the [OK] button.

    → Setting of the subsystem parameter starts.

  4. Click the [Done] button to return to the [System Settings] screen.