Planning to set up Oracle RAC on IBM System z

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There are several major decision points when planning to build an Oracle RAC system on Linux™ on IBM® System z®, such as:

  • Disk storage type (DASD or SCSI)
  • Network device type for the Oracle Interconnect – HiperSockets™, 10 Gb Ethernet, or 1 Gb Ethernet
  • Linux distribution
  • Shared disk management (Cluster file system or ASM)

Disk storage type

With IBM System z, the storage can be set up as disk storage type DASD or SCSI. This study used the device type DASD, which implements the Extended Count Key Data (ECKD™) interface. The FICON® Express® cards that are the channel adapters are set up as type FICON. The IBM developerWorks® website provides techniques for working with disk devices on IBM System z with Linux. See

https://www.ibm.com/developerworks/linux/linux390/perf/tuning_diskio.html

Network device type for the Oracle interconnect

HiperSockets

HiperSockets are a high speed and high-bandwidth I/O function on IBM System z that communicates between Logical Partitions (LPARs). While the interface for a HiperSockets connection is configured on Linux on IBM System z in the same manner as an OSA device, the transmission of the data takes place within the central processor complex (CPC) using the memory bus rather than the I/O bus, and this data transmission has a very short latency time. In an ordinary transmission on IBM System z, every I/O must minimally be processed by the I/O subsystem, including the channel adapter, and then connected externally.

HiperSockets is also a secure way to handle data traffic, because it is an isolated point to point connection. Oracle RAC clustering requires a fast private interconnect, to keep the server nodes' shared caches consistent. HiperSockets hardware should be the first choice for Oracle RAC nodes on LPARs on the same physical IBM System z.

1 Gb versus 10 Gb Ethernet

An alternative interconnect device is the 10 Gb OSA card. It has a bandwidth of 10 Gb. The use of a 1 Gb network connection for the Oracle RAC interconnect should be considered very carefully.

Linux distribution on IBM System z

Both Linux distributions, Novell SUSE Linux Enterprise Server (SLES) and Red Hat Enterprise Linux are supported for Oracle RAC on Linux on IBM System z. This study used SLES 10 SP2.