Lucent Technologies 585-210-940 User Manual
Introduction to Disk Mirroring
CentreVu CMS Release 3 Version 8 Disk-Mirrored Systems
Disk mirroring defined
2
The illustration below shows a simple, two-slice metadevice.
Concatenated
metadevices
metadevices
1
A metadevice can be configured as any one of three basic types:
striped,
concatenated, or concatenated stripes. The type used by CMS systems
is the concatenated metadevice. In a concatenated metadevice, data
blocks, or
is the concatenated metadevice. In a concatenated metadevice, data
blocks, or
chunks, are written sequentially across the slices, beginning
with the first disk.
Consider, for example, a concatenated metadevice with three slices (see
the illustration below.) In that scenario, disk A can be envisioned as
containing logical chunks 1 through 4, disk B as containing logical
chunks 5 through 8, and disk C as containing chunks 9 through 12.
the illustration below.) In that scenario, disk A can be envisioned as
containing logical chunks 1 through 4, disk B as containing logical
chunks 5 through 8, and disk C as containing chunks 9 through 12.
c0t0d0s2
c1t0d0s2
c0t0d0s2
Physical Disks A & B
Metadevice d0
c1t0d0s2
Chunk 3
Chunk 4
Chunk 2
Chunk 1
Chunk 7
Chunk 8
Chunk 6
Chunk 5
Chunk 11
Chunk 12
Chunk 10
Chunk 9
Solstice DiskSuite
. . .
Chunk 2
Chunk 1
Chunk 12
. . .
. . .
Physical Disk A
Physical Disk B
Physical Disk C
Metadevice d1