Exacerbating this problem, in some industries and particularly in public companies, regulations require the stringent protection of corporate and customer data. Thus, some companies cannot consolidate AIX servers onto System i unless they have a tool protecting their data in that environment.
In the past, the few HA tools that did exist for AIX on System i were generally very expensive, rendering them not financially viable in many situations. Vision's product offerings on AIX, MIMIX EchoStream and MIMIX HA Cluster, offer cost-effective solutions that provide HA for applications and data running either on System p or on AIX running on a System i partition.
System i users running native i5/OS applications have come to depend on that platform's reliability and stability. Consequently, when they consider HA, they often think primarily in terms of data protection, with reliable, low-latency data replication being the primary concern. Switchover and failover capabilities are required to recover operations after a disaster or when the primary System i server needs to be taken offline for maintenance, but the switchover capabilities are not considered in isolation from the replication component of an HA solution.
HA on System p has generally followed a different path. Because expected up-times are not quite as high on System p as on System i, HA in the System p world historically tended to focus on server failover facilities, with data protection provided largely by data backups and disk technologies such as RAID. Thus, Vision offers two solutions, MIMIX HA Cluster for AIX and MIMIX EchoStream for AIX, that can be used alone or in combination.
MIMIX HA Cluster continuously monitors the AIX environment, regardless of whether it's running standalone or within a System i partition. When HA Cluster detects a problem on the primary server, it fails over to a backup AIX server or partition. All aspects of the failover—including dismounting the storage, switching the IP address, remounting the storage, and starting up the application—are performed automatically to minimize downtime and labor costs. To prevent the execution of unnecessary failovers, when a network failure is detected, instead of a failover being triggered, network connections are automatically rerouted. The MIMIX HA Cluster GUI also allows you to quickly switch users to the backup when maintenance is required on the primary server.
MIMIX EchoStream protects data by replicating it in near real time from a primary data store to a local or remote backup data store. Unlike many other replication products, EchoStream provides Continuous Data Protection (CDP), which allows you to restore data to a particular point in time, rather than to only the point of failure.
This CDP functionality solves one of the often unmentioned problems of traditional data replication—namely, what do you do when a portion of the data is corrupted but the data store is otherwise generally intact? When a disk drive crashes or a simultaneous error corrupts a RAID data store, the problem is obvious. Systems stop and you know what you have to do: switch to the backup data store.
In contrast, when data is corrupted, systems may continue to operate and the replicator will transmit the corrupted data to the backup data store, corrupting it as well. Without the ability to recover to a point before the corruption occurred, considerable manual labor is usually required to repair the damage. CDP, on the other hand, allows you to reverse data corruption in a fraction of the time and at a fraction of the labor costs, as compared to a manual approach.
The bottom line is that Vision products offer an affordable way to supply the same high level of availability for AIX servers integrated into System i as you've come to expect on native i5/OS environments.