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A robust complement to the operating system’s I/O |
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The AIX operating system integrates facilities in its code for managing redundant access to disks and re-allocating the corresponding paths. This is generically referred to as the multipath infrastructure (MPIO framework). This environment requires specific modules to make the infrastructure operational, in particular for compatibility with the storage racks used. Bull thus offers a set of coherent modules to facilitate and stabilize the SAN environments.
The main feature in the StoreWay MultiPath software for AIX is the management of input-output physical paths to disks or, more precisely, to a LUN (Logical Unit Number) both during normal operation periods and in case of any failure on one of the paths. The detection of any input-output error on a path is captured by the software which, rather than reporting the error to the applicative program, switches the input-output to a second available path. |
Automatic or manual recovery for optimized service quality |
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After a faulty path has been repaired (Fibre Channel adapter, SAN infrastructure cable or element, etc.), the resumption of the inputs-outputs to the initial path (referred to as primary) can either be automatic – detected by StoreWay MultiPath, or manual on the administrator’s initiative. To implement this failback, StoreWay MultiPath uses a "health check" path monitoring mechanism. |
Better response times through load distribution |
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StoreWay MultiPath for AIX incorporates load distribution functions for authorizing simultaneous use of the different paths available to access the same LUN. This mechanism optimizes the traffic and avoids bandwidth bottlenecks. |
Higher availability |
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The StoreWay MultiPath module for AIX implements support mechanisms that use SCSI-3 reservation-type commands. To ensure data coherency when switching nodes in a cluster, this mechanism is essential in a cluster environment, whether managed using Bull’s HA-CMP or ARF (Application Roll-over Facilities) solutions. It avoids any access to disks by the faulty node at the moment of the failback to the second node, and thus ensures data integrity. |
Data protection and system boot |
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StoreWay MultiPath supports the AIX boot process: the data and operating system thus benefit from an additional guarantee of secure, continuous access. |
Services and support |
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Bull offers professional services and a choice of support for optimal operation. |
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