Understanding Nss Mirroring - Novell OPEN ENTERPRISE SERVER 2 SP 2 - CLUSTER SERVICES 1.8.7 FOR LINUX Manual

10.10.1 Understanding NSS Mirroring

NSS mirroring is a checkpoint-based synchronous mirroring solution. Data blocks are written
synchronously to multiple storage devices. It is an alternative to synchronous replication options that
are provided by a SAN array.
Hardware configuration and placement for NSS mirroring can vary depending on geography and
fault tolerance requirements. For example, Figure 10-1 depicts a simple hardware configuration in
which one side of the mirrored NSS volume is located in a separate building from the rest of the
cluster hardware. If a disaster occurs in one building, data is still safe on the mirrored NSS volume
in the other building.
Single Cluster with Mirrored NSS Volumes in Separate Buildings
Figure 10-1
Red Cluster
Switch
Fibre Channel
Mirrored
NSS Volumes
Fibre Channel Arrays
Fibre Channel Arrays
Figure 10-2 depicts a more complex hardware configuration in which two clusters are placed in
separate buildings, but each has one side of a mirrored NSS volume in the building with the other
cluster. If a disaster occur in one building, data is still safe and immediately accessible on the
mirrored NSS volume in the other building.
Configuring Cluster Resources for Shared NSS Pools and Volumes 151