Understanding and Designing Serviceguard Disaster Recovery Architectures

Figure 10 Two Data Centers and Third Location with Arbitrators or a Quorum Server
Node 1
Node 2
Network
Switch
Network
Switch
Network
Switch
Network
Switch
Network
Switch
Network
Switch
Arbitrator
Data Center A Data Center B
Third Location
Power
Circuit 5
Power
Circuit 6
Local XP
Disk Array
Remote XP
Disk Array
Power
Circuit 2
Power
Circuit 1
Power
Circuit 3
Power
Circuit 4
Node 1
Node 2
PV Links
PV Links
PV Links
PV Links
Arbitrator
Quorum
Server
replicated data for package B
replicated data for package A
PVOL --------------------------------------- SVOL
PVOL --------------------------------------- SVOL
replicated data for package C
replicated data for package D
SVOL --------------------------------------- PVOL
SVOL --------------------------------------- PVOL
Highly Available network
Continous Access Link
pkg B
pkg A
pkg C
pkg D
A
D
1
B
C
1
C
B
1
D
A
1
Main disk array for one set of packages can also be the remote disk array for another package.
In Figure 10 (page 23), the P9000 or XP disk array in data center A is the main or primary disk
array for packages A and B, and the remote or secondary disk array for packages C and D in
data center B. For packages A and B, data is written to PVOLs on the array in Data Center A and
replicated to SVOLs on the array in Data Center B. Similarly, P9000 or XP disk array in Data
Center B is the primary or main disk array for packages C and D, and the secondary or remote
for packages A and B. For packages C and D, data is written to PVOLs on the disk array in Data
Center B and replicated to SVOLs in Data Center A.
NOTE: On HP-UX, cluster lock devices are not supported as arbitrators because cluster locks
cannot be maintained across the replication link, such as Continuous Access, SRDF, or 3PAR
Remote Copy.
On Linux, Lock Lun devices are not supported as arbitrators because Lock Lun cannot be maintained
across the replication link, such as Continuous Access or 3PAR Remote Copy.
Understanding Metrocluster 23