Installation guide

Table 4–2: Differences in Disk Shadowing Facilities
ULTRIX Disk Shadowing LVM
Description
A layered product that enables
you to replicate data on disk
partitions.
A kernel subsystem that
enables you to create and
manage logical volumes.
Additionally, you can replicate
data and create logical volumes
that span multiple disks.
Partitions
Supports root, swap, and
data partitions
Supports data partitions, but
does not support root and
swap partitions
Metadata Size
4kB 70kB−4MB
Terminology
Disk shadowing Data mirroring
Shadow device Logical volume
Disk partition Physical volume
Metadata Metadata
Shadow set Set of physical volumes used in
a mirrored logical volume
Two-member shadow set Single mirrored data
Three-member shadow set Double mirrored data
None Physical extent (contiguous
disk region)
None Logical extent (contiguous
logical region that maps to 1, 2,
or 3 physical extents)
None Volume group (set of physical
and logical volumes)
For information on migrating shadowed data from an ULTRIX system to a
DIGITAL UNIX system, see Section 5.2.
4.11 Networking Support
The DIGITAL UNIX system includes the following networking support:
• Transmission Control Protocol/Internet Protocol (TCP/IP) software and
associated applications, such as telnet, Berkeley remote commands
and utilities, and Simple Network Management Protocol (SNMP) Agent
software
• DECnet software
4–18 Overview of DIGITAL UNIX System and Network Administration