Installation guide

CD−ROM discs, use the −d option to the mount command. See mount(8) for
more information.
5.2 Migrating Shadowed Data
This section describes migration from the ULTRIX Disk Shadowing product
to the DIGITAL UNIX Logical Volume Manager (LVM) software.
_______________________ Note _______________________
This section does not discuss migration to the Logical Storage
Manager (LSM) software on DIGITAL UNIX systems. For
migration information about LSM, see the Logical Storage
Manager manual.
Before migrating ULTRIX shadowed data to a DIGITAL UNIX system,
review the following guidelines:
• The LVM subsystem has a broader management scope than the
ULTRIX Disk Shadowing product. Nevertheless, the migration strategy
presented in this section only focuses on the disk mirroring aspects of
the LVM subsystem. For a complete description of the LVM subsystem,
see the System Administration manual.
• You must have root privilege on the DIGITAL UNIX system to mirror
data using the LVM subsystem.
• Creating physical volumes, which is an LVM concept, on a raw partition
overwrites the existing data on that partition.
• An ULTRIX shadow device can only consist of corresponding partitions
on physical disks of the same type. Logical volumes do not have this
restriction.
• You cannot migrate shadowed root and swap partitions to the LVM
subsystem.
• Consider the user data size and the metadata size when allocating
partitions for LVM physical volumes:
– User data
If the existing ULTRIX shadowed partition is nearly full, migrate
the data to a larger partition.
– Metadata
A DIGITAL UNIX system requires more physical space to replicate
data than an ULTRIX system requires because the LVM metadata
uses more disk space. Use the default LVM parameters for
Migrating Your ULTRIX System and Network Environment 5–3