Systems and connection methods for OCFS2

The servers and their communication methods for the OCFS2 study are described in detail.

The cluster of two Linux® servers created with SLES 10 SP1 is installed on separate Logical Partitions (LPARs) of an IBM® System z10™. A Linux server installed on an LPAR can be configured with dedicated or shared resources, including processor, memory, and I/O devices. Each Linux LPAR uses two dedicated processors and 2 GB of memory.

Each Linux server uses dedicated storage for their SLES 10 SP1 operating system and user home directories on non-shared disks formatted with EXT3, and shared disks formatted with OCFS2. All of the physical disks were RAID arrays on an IBM System Storage™ DS8000®, large external disk storage unit.

The communication channel between the servers for sharing the disks is used to communicate cluster membership status and other cluster-related messages between cluster members. Communication channels can be implemented with a wired Ethernet network (for example, a LAN), or on the IBM System z® with a HiperSockets™ connection. IBM System z HiperSockets are very fast internal channels between LPARs on the same physical machine, which operate directly in the memory from the IBM System z10 Central Electronic Complex (CEC), without any external cables or switches. The short latency time of HiperSockets communications compared with other internode communications makes IBM System z suitable for clustered applications.