Frequently Asked Questions About RAID 1 (Mirror) Volumes

Why would I use a mirror?

For maximum data availability. The trade-off is that a mirror requires twice the number of slices (disks) as the amount of data to be mirrored.

How many submirrors can a mirror contain?

Solaris Volume Manager allows you to create up to a three-way mirror (a mirror of three submirrors). However, two-way mirrors usually provide sufficient data redundancy for most applications, and are less expensive in terms of disk drive costs.

Why should I create a one-way mirror then attach additional submirrors?

If you have existing data that you are mirroring, you must create the primary submirror, then attach additional submirrors so they can be updated with the data that is contained in the primary submirror.

When should I create a two-way or three-way mirror with a single command?

If you have no existing data that you are mirroring and you are comfortable destroying all data on all submirrors, you can speed the creation process by creating all submirrors with a single command.