General Guidelines for Creating Mirrored File Systems

Specifying a Volume

You can choose to specify a mirror or submirror or allow the lucreate command to choose a free volume for you.

• To specify a volume, append a comma and the name of the submirror or mirror to the device name. In the following option, the submirror d1 is specified.

  -m /:/dev/dsk/c0t0d0s0,d1:attach

• To enable the software to choose a free volume, do not name the submirror or mirror. In this option, the submirror is not specified, and the software chooses a free volume.

  -m /:/dev/dsk/c0t0d0s0:attach

Volume Naming Shortcuts

You can abbreviate the names of physical disk slices and Solaris Volume Manager volumes. The abbreviation is the shortest name that uniquely identifies a device. Examples follow.

• A Solaris Volume Manager volume can be identified by its dnum designation, so that, for example, /dev/md/dsk/d10 becomes simply d10.

• If a system has a single controller and multiple disks, you might use t0d0s0, but with multiple controllers use c0t0d0s0.

For more information on naming requirements and guidelines, see “Overview of Solaris Volume Manager Components” in Solaris Volume Manager Administration Guide.

Checking Status of Volumes

If a mirror or submirror needs maintenance or is busy, components cannot be detached. You should use the metastat command before creating a new boot environment and using the detach keyword. The metastat command checks if the mirror is in the process of resynchronization or if the mirror is in use. For information, see the man page metastat(1M).

Detaching Volumes and Resynchronizing Mirrors

If you use the detach keyword to detach a submirror, lucreate checks if a device is currently resyncing. If the device is resyncing, you cannot detach the submirror and you get an error message.

Resynchronization is the process of copying data from one submirror to another submirror after the following problems:

• Submirror failures.

• System crashes.

• A submirror has been taken offline and brought back online.

• The addition of a new submirror.

For more information about resynchronization, see “RAID 1 Volume (Mirror) Resynchronization” in Solaris Volume Manager Administration Guide.

Using Solaris Volume Manager Commands

Use the lucreate command rather than Solaris Volume Manager commands to manipulate volumes on inactive boot environments. The Solaris Volume Manager software has no knowledge of boot environments, whereas the lucreate command contains checks that prevent you from inadvertently destroying a boot environment. For example, lucreate prevents you from overwriting or deleting a Solaris Volume Manager volume.

However, if you have already used Solaris Volume Manager software to create complex Solaris Volume Manager concatenations, stripes, and mirrors, you must use Solaris Volume Manager software to manipulate them. Solaris Live Upgrade is aware of these components and supports their use. Before using Solaris Volume Manager commands that can create, modify, or destroy volume components, use the lustatus or lufslist commands. These commands can determine which Solaris Volume Manager volumes contain file systems that are in use by a Solaris Live Upgrade boot environment.