Arbitration For Data Integrity in Serviceguard Clusters, July 2007

Arbitration for Data Integrity in Serviceguard Clusters
Summary
31
Quorum Server • Can be used with
clusters of any size.
• Can serve up to 50
clusters/100 nodes.
• Can be used HP-UX and
Linux clusters at the
same time.
• Is free on the Distributed
Components CD (shipped
along with the SG
product CD).
• Provides faster failover
time than cluster lock
disk.
• Requires a separate system not
part of the cluster.
• Only one IP address is used for
quorum server.
• Does not permit multiple physical
network pathways unless APA
(auto port aggregation) or channel
bonding is used. LAN failure will
remove the QS from
communication with the cluster,
though the cluster remains
running.
Arbitrator Nodes • Offers protection for the
loss of an entire data
center in a metropolitan
or extended distance
cluster.
• Allows arbitration to be
done over longer
distances than disk
locking.
• Arbitrator nodes can be
used for other
non-cluster applications.
• Additional Serviceguard licenses
required for arbitrator nodes.
• Additional hardware must be
provided, often in a data center
that is on a separate site.
• For those with multiple clusters,
arbitrator nodes can be very
costly.
Table 1 Comparison of Different Arbitration Methods (Continued)
Arbitration
Mode
Advantages Disadvantages