HP serviceguard t2808-90006 manual 33

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)
Maximum	100 Kilometers	Shortest of the distances		No distance
Distance		between:		restrictions.
		•	Cluster network
			latency (not to
			exceed 200 ms).
		•	Data Replication
			Max Distance.
		•	DWDM provider
			max distance.
Data	Host-based, through	Array-based, through		You have a choice of
Replication	MD. Replication can	Continuous Access XP or		either selecting their
mechanism	affect performance	Continuous Access EVA.		own SG-supported
	(writes are	Replication and		storage and data
	synchronous).			replication
		resynchronization
	Resynchronization can			mechanism, or
		performed by the storage
	impact performance.			implementing one of
		subsystem, so the host
	(Complete			HP’s pre-integrated
		does not experience a
	resynchronization is			solutions (including
		performance hit.
	required in many			Continuous Access XP,
		Incremental
	scenarios that have			Continuous Access
		resynchronizations are
	multiple failures.)			EVA, and EMC SRDF
		done, based on bitmap,
				for array-based, or
		minimizing the need for
				Oracle 8i Standby for
		full re-syncs.
				host based.) Also, you
				may choose Oracle 9i
				Data Guard as a
				host-based solution.
				Contributed (that is,
				unsupported)
				integration templates
				for Oracle 9i.

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