Installation guide

On a clustered volume group, the following command can be used to create a cluster aware
mirror:
# lvcreate -m1 -L 1G -n my_new_lv my_vg
4.10 Cluster Resource Manager
The Cluster Resource Manager (rgmanager) manages and provides failover capabilities for
cluster resource groups. It controls the handling of user requests including service start,
restart, disable, and relocate.
The service manager daemon also handles restarting and relocating services in the event of
failures. Rgmanager uses Open Cluster Framework (OCF) compliant resource agents to
control and monitor required resources. SAPInstance and SAPDatabase are OCF compliant
resource agents provided by Red Hat.
In Red Hat Enterprise Linux 5.3, rgmanager includes an event driven scripting mechanism
called RIND (Rind Is Not Dependencies). RIND can be used to create complex event driven
service dependencies. For automatic enqueue replication failover scenarios, the RIND based
follow_service dependency is required.
4.11 Shared Root Cluster
Modern data center concepts are treating server and storage hardware independently. SAN
or Network Attached Storage (NAS) devices are used to store and protect all critical data.
Hence, servers are no longer tied to a single operating system installation and can be used in
more flexible manners. All servers are booted directly from the shared storage arrays.
A single cluster wide OS installation can be placed upon a shared file system such as NFS or
GFS. The installation can easily be shared by all servers in a cluster. In this manner, a
diskless, shared root cluster with a file system based Single System Image (SSI) is achieved.
The open-sharedroot cluster enhancement must be installed to create a Red Hat Enterprise
Linux based diskless shared root cluster.
4.12 Scalability
Within a diskless shared root cluster, the server scaling is independent from storage scaling.
If a diskless shared root cluster needs more CPU resources one simply needs to add new
servers on the fly.
4.13 Availability
In a shared root cluster, cluster wide operating system configuration consistency is assured
and required to ensure reliable failover mechanisms.
4.14 Management
One of the key advantages of a diskless shared root cluster is the ease of management.
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