Installation guide

1> sp_configure 'enable java', 1
2> go
Multipathing
Multipathing is the ability of a server to communicate with the same physical or logical block
storage device across multiple physical paths between the host bus adapters (HBA) in the
server and the storage controllers for the device, typically in Fibre Channel (FC) or iSCSI
SAN environments. You can also achieve multiple connections with direct attached storage
when multiple channels are available.
Multipathing provides connection fault tolerance, failover, redundancy, high availability, load
balancing, and increased bandwidth and throughput across the active connections.
Multipathing automatically isolates and identifies device connection failures, and reroutes I/O
to alternate connections.
Typical connection problems involve faulty adapters, cables, or controllers. When you
configure multipath for a device, the multipathing driver monitors the active connection
between devices. Because multipathing is managed at the device level, when the multipath
driver detects I/O errors for an active path, it fails over the traffic to the device’s designated
secondary path. When the preferred path becomes healthy again, control can be returned to the
preferred path. Multipathing prevents single points of failure in any highly available system.
A common example of multipath connectivity is a SAN-connected storage device. Usually
one or more Fibre Channel HBAs from the host is connected to the fabric switch and the
storage controllers are connected to the same switch. A simple example of multipath
connectivity is: two HBAs connected to a switch to which the storage controllers are
connected. In this case the storage controller can be accessed from either of the HBAs
providing multipath connectivity.
All OS platforms provide their own solutions to support multipathing. There are numerous
other vendors that also provide multipathing applications for all available platforms, such as:
• AIX – Multiple Path I/O (MPIO)
• HP-UX 11.31 – Native MultiPathing (nMP)
• Linux – Device-Mapper Multipath (DM)
• Solaris – Multiplexed I/O (MPxIO)
• AntemetA Multipathing Software for HP EVA Disk Arrays
• Bull StoreWay Multipath
• NEC PathManager
• EMC PowerPath
• FalconStor IPStor DynaPath
• Fujitsu Siemens MultiPath
• Fujitsu ETERNUS Multipath Driver
• Hitachi HiCommand Dynamic Link Manager (HDLM)
• HP StorageWorks Secure Path
CHAPTER 5: Planning Your Adaptive Server Installation
34 Adaptive Server Enterprise