Changing Solaris Volume Manager Defaults

The Solaris Volume Manager configuration has the following default values:

• 128 volumes per disk set

• d0 through d127 as the namespace available for use by volumes

• 4 disk sets

• State database replica maximum size of 8192 blocks

The default values of total volumes, namespace, and number of disk sets can be changed, if necessary. The tasks in this section tell you how to change these values.

How to Increase the Number of Default Volumes

The nmd field in the /kernel/drv/md.conf file allocates the number of volumes allowed and the namespace available for volumes. This task describes how to increase the number of volumes from the default value of 128 and the namespace from the default range of d0 through d127. If you need to configure more volumes than the default allows, you can increase this value up to 8192.

If you lower this number at any point, any volume existing between the old number and the new number might not be available, potentially resulting in data loss. If you see a message such as “md: d200: not configurable, check /kernel/drv/md.conf,” you must edit the md.conf file and increase the value, as explained in this task.

Before You Begin

Review Prerequisites for Troubleshooting the System.

Steps

1. Edit the /kernel/drv/md.conf file.

2. Change the value of the nmd field. Values up to 8192 are supported.

3. Save your changes.

4. Perform a reconfiguration reboot to build the volume names.

   # reboot -- -r

Example 22–3 Increasing the Number of Default Volumes

Here is a sample md.conf file that is configured for 256 volumes.

#
#ident "@(#)md.conf   1.7     94/04/04 SMI"
#
# Copyright (c) 1992, 1993, 1994 by Sun Microsystems, Inc.
#
#
#pragma ident   "@(#)md.conf    2.1     00/07/07 SMI"
#
# Copyright (c) 1992-1999 by Sun Microsystems, Inc.
# All rights reserved.
#
name="md" parent="pseudo" nmd=256 md_nsets=4;

How to Increase the Number of Default Disk Sets

This task shows you how to increase the number of disk sets from the default value of 4.

Do not decrease the number of default disk sets if you have already configured disk sets. Lowering this number could make existing disk sets unavailable or unusable.

Before You Begin

Review Prerequisites for Troubleshooting the System.

Steps

1. Edit the /kernel/drv/md.conf file.

2. Change the value of the md_nsets field. Values up to 32 are supported.

3. Save your changes.

4. Perform a reconfiguration reboot to build the volume names.

   # reboot -- -r

Example 22–4 Increasing the Number of Default Disk Sets

Here is a sample md.conf file that is configured for five shared disk sets. The value of md_nsets is 6, which results in five shared disk sets and one local disk set.

#
#
#pragma ident   "@(#)md.conf    2.1     00/07/07 SMI"
#
# Copyright (c) 1992-1999 by Sun Microsystems, Inc.
# All rights reserved.
#
name="md" parent="pseudo" nmd=128 md_nsets=6;
# Begin MDD database info (do not edit)
...
# End MDD database info (do not edit)