O2Cb Cluster Service; Disk Heartbeat - Novell LINUX ENTERPRISE SERVER 10 - INSTALLATION AND ADMINISTRATION 08-05-2008 Installation Manual

14.1 O2CB Cluster Service

The O2CB cluster service is a set of modules and in-memory file systems that are re-
quired to manage OCFS2 services and volumes. You can enable these modules to be
loaded and mounted during system boot. For instructions, see
uring OCFS2 Services"
Table 14.1 O2CB Cluster Service Stack
Service
Node Manager (NM)
Heartbeat (HB)
TCP
Distributed Lock Manager
(DLM)
CONFIGFS
DLMFS

14.2 Disk Heartbeat

OCFS2 requires the nodes to be alive on the network. The O2CB cluster service sends
regular keepalive packages to ensure that they are alive. It uses a private connection
between nodes instead of the LAN to avoid network delays that might be interpreted
as a node disappearing and thus, lead to a node's self-fencing.
(page 294).
Description
Keeps track of all the nodes in the /etc/ocfs2/
cluster.conf file
Issues up/down notifications when nodes join or leave
the cluster
Handles communications between the nodes with the
TCP protocol
Keeps track of all locks and their owners and status
User space configuration file system. For details, see
Section 14.3, "In-Memory File Systems"
User space interface to the kernel space DLM. For de-
tails, see Section 14.3, "In-Memory File Systems"
(page 290)
Section 14.6.2, "Config-
(page 290)
Oracle Cluster File System 2 289