Network Router User Manual

18 Sun StorEdge Network Data Replicator 3.0 Configuration Guide • June 2001
One-to-Many and Multihop Volume Sets
The Sun SNDR software enables you to create one-to-many and multihop volume
sets.
In a one-to-many volume set, you can replicate data from one primary volume to
many secondary volumes residing on one or more hosts. One primary and each
secondary host volume is a single volume set (each secondary volume requires its
own unique secondary bitmap volume). When you perform a forward
resynchronization, you can synchronize one volume set or all volume sets; in this
case, issue a separate command for each set. You can also update the primary
volume by using a specific secondary volume.
FIGURE 1 shows one primary and
three secondary host volumes and therefore three volume sets: A and B1, A and B2,
and A and B3.
Note – You can group one-to-many sets that share a common primary volume in a
single I/O group to operate on all sets simultaneously instead of issuing a separate
command for each set. See also “Order-Dependent Writes and Volume Set
Grouping” on page 13.
In a multihop set, the secondary host volume of one volume set can be the primary
host volume of another volume set.
FIGURE 1 shows one primary and one secondary
host volume; the secondary host volume B becomes the primary host volume A1 to
the secondary host volume B1.
FIGURE 1 One-to-Many and Multihop Volume Sets
Primary host volume
Secondary host volume
Secondary host volume
Secondary host volume
/dev/rdsk/c0t0d0s5
/dev/rdsk/c0t0d0s7
/dev/rdsk/c0t0d0s9
/dev/rdsk/c0t0d0s5
One-To-Many
Primary host volume Secondary host volume Secondary host volume
/dev/rdsk/c0t0d0s5 /dev/rdsk/c0t0d0s5/dev/rdsk/c0t0d0s5
Multihop
One volume set Another volume set
A
B1
B2
B3
A1
B
A = Primary host volume
B = Secondary host volume
A
B1