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Sun Cluster 2.2 System Administration Guide

Enabling and Disabling NVRAM

Fast writes can be configured:

When fast write is enabled, it can be saved--across power cycles--as part of the SPARCstorage Array's configuration.

If the NVRAM battery is low, missing, or has failed, then fast write is disabled on the controller.

Before enabling fast write, you must stop all I/O to the controller or disk. In particular, ensure that diskset ownership has been released because an implicit I/O stream exists while ownership of a diskset is maintained. The following procedure explains how to stop all I/O.

Use the luxadm(1M) command to enable and disable NVRAM. Refer to the luxadm(1M) man page for complete information on this command.

Note -

For VxVM cluster feature (as used with Oracle Parallel Server), you should disable NVRAM.

How to Enable and Disable NVRAM

These are the high-level steps to enable or disable NVRAM:

These are the detailed steps to enable or disable NVRAM.

  1. Identify the controller, tray, or individual disk whose NVRAM is to be enabled or disabled.

    You can use the luxadm(1M) command to display information for a specified controller, tray, or individual disk. For example, the following display identifies all of the disks on Controller c2.


    phys-hahost1# luxadm display c2
                     SPARCstorage Array Configuration

Controller path:
/devices/iommu@f,e0000000/sbus@f,e0001000/SUNW,soc@0,0/SUNW,pln@a0000000,779a16:ctlr
                          DEVICE STATUS
      TRAY 1                 TRAY 2                 TRAY 3
slot
1     Drive: 0,0             Drive: 2,0             Drive: 4,0
2     Drive: 0,1             Drive: 2,1             Drive: 4,1
3     NO SELECT              NO SELECT              NO SELECT
4     NO SELECT              NO SELECT              NO SELECT
5     NO SELECT              NO SELECT              NO SELECT
6     Drive: 1,0             Drive: 3,0             Drive: 5,0
7     Drive: 1,1             NO SELECT              NO SELECT
8     NO SELECT              NO SELECT              NO SELECT
9     NO SELECT              NO SELECT              NO SELECT
10    NO SELECT              NO SELECT              NO SELECT
                         CONTROLLER STATUS
...

  2. Stop all I/O to the affected device.

    Solstice DiskSuite:

    VxVM:

  3. Enable or disable fast write on the controller or individual disk.

    Use one of the three options to the luxadm(1M) command, depending on whether you are enabling fast write for all writes, enabling fast write only for synchronous writes, or disabling fast write.

    • -e enables fast write for all writes

    • -c enables fast write for only synchronous writes

    • -d disables fast write

    The following example saves the NVRAM configuration across power cycles and enables fast write for all writes. See the luxadm(1M) man page for details on these options.


    phys-hahost# luxadm fast_write -s -e pathname

    A confirmation appears, indicating that fast write has been enabled.

  4. Perform the steps needed to bring the component into normal operation under Sun Cluster.

    Solstice DiskSuite:

    VxVM: