HP serviceguard t2808-90006 manual Understanding Types of Disaster Tolerant Clusters

Disaster Tolerance and Recovery in a Serviceguard Cluster

Understanding Types of Disaster Tolerant Clusters

Table 1-1	Comparison of Disaster Tolerant Cluster Solutions (Continued)
Attributes	Extended Distance	CLX	Continentalclusters
	Cluster		(HP-UX only)
Key	No ability to check the	Specialized storage	No automatic failover
Limitation	state of the data before	required. Currently, XP	between clusters.
	starting up the	with Continuous Access,
	application. If the	and EVA with
	volume group (vg) can	Continuous Access are
	be activated, the	supported.
	application will be
	started. If mirrors are
	split or multiple paths
	to storage are down, as
	long as the vg can be
	activated, the
	application will be
	started.
	Data resynchronization
	does not have a big
	impact on system
	performance. However,
	the performance varies
	depending on the
	number of times data
	resynchronization
	occurs. In the case of
	MD, data
	resynchronization is
	done one disk at a time,
	using about 10% of the
	available CPU time
	and taking longer to
	resynchronize multiple
	LUNs. The amount of
	CPU time used is a
	configurable MD
	parameter.

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