Installation guide

called ULTRIX Disk Shadowing. The ULTRIX Disk Shadowing product is
not available on DIGITAL UNIX systems. To replicate data on a DIGITAL
UNIX system, use the Logical Storage Manager (LSM) subsystem.
4.10.1 Logical Storage Manager
The DIGITAL UNIX Logical Storage Manager (LSM) is an integrated,
host-based disk storage management tool that protects against data loss
and improves disk I/O performance. System administrators use LSM to
perform disk management functions including disk concatenation, data
mirroring or shadowing, and striping.
LSM builds virtual disks, called volumes, on top of UNIX system disks.
LSM permits dynamic reconfiguration of its disk volumes, making it easy
to adapt to changes in I/O load and application needs, and to maximize
system availability. LSM features a high degree of flexibility in the way
volumes can be mapped to disk and partition devices. This flexibility allows
you to optimize performance, change volume size, add mirrors, and perform
backups or other administrative tasks without interrupting system
applications and users.
LSM includes a command-line interface, a menu interface, and a
windows-based interface that a system administrator can use to
transparently optimize I/O performance, change volume size, add plexes,
and perform backups or other administrative tasks.
Migration information is contained in the Logical Storage Manager manual.
4.10.2 Logical Volume Manager
To replicate data on earlier versions of DIGITAL UNIX systems, the
Logical Volume Manager (LVM) subsystem was used. This subsystem has
been retired in favor of the LSM subsystem.
_______________________ Note _______________________
The LVM subsystem and the ULTRIX Disk Shadowing product
use incompatible on-disk metadata formats. Consequently, you
cannot mount an existing ULTRIX shadowed file system on an
LVM mirrored logical device without converting.
Table 4–2 shows some of the differences between the ULTRIX Disk
Shadowing product and the LVM subsystem.
Overview of DIGITAL UNIX System and Network Administration 4–17