Configuration

Overview

This section provides guidance on managing storage and multipath I/O (MPIO) settings, including iSCSI target configuration, disk rescans, console refreshing, MPIO policy adjustments, and virtual disk properties.

This topic includes:

Configuring iSCSI Targets for MPIO

If using iSCSI, configure the Microsoft iSCSI Initiator software to add target portals to the DataCore Servers and log on to those connections.

  • iSCSI targets should be configured prior to serving virtual disks from the storage servers to the hosts.
  • When making connections, do not select the Enable multi-path check box.

To configure iSCSI targets:

  1. On the host, discover the target portal using the IP address or DNS name.
  2. Log on to the target. Ensure that the connection will be automatically restored when the system restarts. The Session State should be Connected.
  3. Configure CHAP or mutual authentication as required.

See Microsoft iSCSI Initiator documentation for additional assistance if needed.

Performing Disk Rescans

This topic will cover the rescan types, how to change automatic rescan settings, and how to do a manual rescan.

Rescan Types

Disk rescans cause virtual disk paths to appear or disappear. Rescans discover new paths or re-acquire paths that were previously lost so that failback can occur. When paths change, event polling is triggered.

Automatic rescans can be event-driven or periodic. Rescans can also be performed manually. See Performing a Manual Rescan.

Normal and fault rescan interval settings can be changed in the console. The default setting for Normal Rescan Interval is every 300 seconds. The default setting for Fault Rescan Interval is every 60 seconds.

Automatic rescans are persistent and occur whether or not the console is open.

Automatic Rescan Types

  • Event-driven performs a query on all paths based on the Normal Rescan Interval to determine if an event has occurred. Events only occur for path changes.
    • Event-driven rescan type uses both normal and fault rescan interval settings. The normal rescan interval is used to query for path changes. If an event occurs such as when paths are detected or lost, disk rescans are performed at the Fault Rescan interval until the failure is resolved.
    • This is the default rescan type setting. DataCore highly recommends keeping the default settings unless instructed to change them by DataCore Technical Support
  • Periodic performs rescans based only on the Normal Rescan Interval setting.
    • The Fault Rescan Interval setting is never used for this type.

This setting should not be used unless specifically instructed to do so by DataCore Technical Support.

Changing the Automatic Rescan Settings

Improper rescan settings may cause I/O errors. DataCore highly recommends that administrators do not change the rescan settings unless instructed by DataCore Technical Support.

To change the settings:

  1. In the DataCore MPIO Console tree, right-click on MPIO Management and select Properties.
  2. Open the Rescan tab.

To change the rescan type:

In the Rescan Type area, select the check box for the desired type.

To change the rescan intervals:

  1. Adjust the number of seconds in the appropriate interval box.
  2. Click OK to save the settings.

Performing a Manual Rescan

To perform an immediate manual rescan:

In the DataCore MPIO Console tree, right-click on MPIO Management and select Rescan Disks.

MPIO Event Polling and Refreshing the Console

The MPIO Console is refreshed based on event polling or automatically at a selected time interval. The intervals used for these settings can be changed. This topic will cover changing the event polling interval, refreshing the console, changing the automatic refresh settings, and performing a manual refresh.

MPIO Event Polling and Refreshing the Console

Event polling is based on certain events that have been detected, such as when a disk has changed, a path has been added or deleted, or when a load balancing policy has changed and refreshes the MPIO Console. The default event polling interval is every 60 seconds.

The event polling interval can be changed, but be aware that the setting will have a performance impact so use caution when increasing the frequency of the interval. When the setting is changed, the console must be closed and re-opened for the change to take effect.

Changing the Event Polling Interval

To change the event polling interval:

  1. In the MPIO Console, right-click on MPIO Management and select Properties.
  2. In the MPIO Management Properties > Console tab, adjust the number of seconds in the Event Polling Interval box.

  3. Click OK.
  4. Close and re-open the console for the change to take effect.

Refreshing the Console

Automatic Refresh detects and updates virtual disk and DataCore Server names in the MPIO Console that have been changed in DataCore SANsymphony software. The console is also refreshed when event polling detects a change. Automatic refresh is enabled by default. The default refresh interval is five minutes. Automatic refresh settings can be changed. Automatic refresh does not affect the operation of MPIO in any way. Refreshes are performed when the console is open and are only used to update information in the console that cannot be detected by an event. Refresh can also be performed manually, see Refreshing the Console.

Changing the Automatic Refresh Settings

The shortest interval that can be set is one minute.

To change the automatic refresh interval:

  1. In the MPIO Console tree, right-click on MPIO Management and select Properties.
  2. In the MPIO Management Properties > Console tab, adjust the number of minutes in the Refresh Interval box.
  3. Click OK.

To disable automatic refresh:

  1. In the MPIO Console tree, right-click on MPIO Management and select Properties.
  2. In MPIO Management Properties > Console tab, clear the Automatic Refresh check box.
  3. Click OK.

Performing a Manual Refresh

To perform a manual refresh:

In the MPIO Console tree, right-click on MPIO Management and select Refresh.

Changing MPIO Policy and Settings

MPIO policy and path settings can be changed for a virtual disk from the MPIO Console. A description of each policy is provided upon MPIO policy selection as shown in the dialog box below.

DSM (Device Specific Module) details can also be viewed and changed. The default DSM is DataCore DSM.

For more information on MPIO policy and settings, consult Microsoft Windows documentation.

To change the MPIO policy and settings:

  1. In the MPIO Console tree, expand Virtual Disks.
  2. Right-click on the virtual disk and select Disk Properties.
  3. Click on the MPIO tab to access the settings.

  4. To view DSM Details and change timer counter settings (which include Path Verify), click Details to open the DSM Details box. Make any changes and click OK to close the box.

  5. To view or change path settings, select the path in the MPIO tab and click Edit to open the MPIO Path Details box. Make any changes and click OK to close the box.

  6. On the MPIO tab, click Apply to save any changes, then click OK to close the Disk Properties dialog box.

Viewing MPIO Disk Properties

The disk properties of a virtual disk can be viewed in the MPIO Console. These are the same properties provided in Windows Disk Management. Some disk properties settings can be changed in the console such as MPIO policy and path settings. For more information on disk properties, consult the Microsoft Management Console Help and Changing MPIO Policy and Settings

To view the properties of a virtual disk:

  1. In the MPIO Console tree, expand Virtual Disks.
  2. Right-click on the virtual disk and select Disk Properties.

 Do not change the write-caching policy for a virtual disk in this dialog box; instead change it in the Virtual Disk Settings in DataCore SANsymphony.