Setting upper-limit values for non-prioritized WWNs: many-to-many connections

After you analyze traffic statistics about prioritized WWNs and non-prioritized WWNs, you must set upper limit values to I/O rates or transfer rates for non-prioritized WWNs. Upper limit values for I/O rates are used to suppress the number of I/Os from the low priority host servers and thus provide better performance for high-priority host servers. Upper limit values for transfer rates are used to suppress the amount of data that is transferred between the storage system and the low priority ports, thus providing better performance for high-priority host servers.

When you set an upper limit for the first time, it is recommended that the upper limit be approximately 90 percent of the peak traffic.

TipTo set the same upper limit value to more than one non-prioritized WWN, use an SPM group. For details on SPM groups, see Working with SPM groups.
NoteYou cannot set the upper-limit value of a host bus adapter that is contained in an SPM group. The upper limit value of a host bus adapter in an SPM group is defined by the SPM group settings. For details, see Setting an upper-limit value to HBAs in an SPM group.
CautionIf an upper limit of the non-prioritized WWN is set to zero or nearly zero, I/O performance might be lowered. If I/O performance is lowered, the host cannot be connected to the storage system in some cases.

Before you begin

  • Required role: Storage Administrator (System Resource Management)
  • You must enable the Device Manager - Storage Navigator secondary window. For details, see Hitachi Device Manager - Storage Navigator User Guide of your storage system.

Procedure

  1. Click Reports Performance Monitor Server Priority Manager to open the Server Priority Manager window.

  2. Click to change to Modify mode.

  3. In the Server Priority Manager window, click Server Priority Manager. The Server Priority Manager main window appears.

  4. Click the WWN tab.

  5. Select whether to limit the I/O rate or the transfer rate of the non-prioritized WWN:

    • To limit the I/O rate, select IOPS from the list at the upper left corner.
    • To limit the transfer rate, select MB/s from the list at the upper left corner.

  6. In the upper-left tree, click the icon of the port whose traffic you want to limit below the Storage System folder.

    The information about the host bus adapters which connect to the selected port is displayed in the list.

  7. Locate the non-prioritized WWN in the list.

    Note
    • The Attribute column of the list indicates whether WWNs are prioritized or non-prioritized. The Attribute column of a non-prioritized WWN displays Non-Prio.
    • If you cannot find any non-prioritized WWN in the list, check the list at the top right corner of the window. If the list displays Prioritize, select All or Non-Prioritize.

  8. Enter the desired upper limit value for the non-prioritized WWN:

    • To enter the upper limit value for the I/O rate, double-click the desired cell in the IOPS column in Upper, and then enter the upper limit value in the cell.
    • To upper limit value for the transfer rate, double-click the desired cell in the MB/s column in Upper, and then enter the upper limit value in the cell.

      In the list, either the IOPS cells or MB/s cells are activated depending on the selected rate. You can specify the limit value by using either the I/O rate or transfer rate for each host bus adapter. The upper limit value that you entered is displayed in blue. You can specify upper limit values by using the I/O rate for some host bus adapters and by using the transfer rate for other host bus adapters.

      NoteIf one host bus adapter is connected to multiple ports and you specify an upper limit value of the host bus adapter for one port, the specified upper limit value is applied to the host bus adapter settings for other connected ports automatically.

  9. Click Apply to apply the settings to the storage system.

    The upper limit value that you entered turns black.
Related Concepts
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