Thursday, November 12, 2009

To know the model of the system:

Usually we use to find the version of the OS installed,
by using
# uname -X
# uname -a
# cat /etc/release

But how to identify the model of the machine?
We can use

OK banner
Which returns the model of the system


# uname -i

bash-3.00# uname -i


Resource type:

Is a collection of properties that describe an application to the cluster. This
collection includes the information about how the application is to be started,
stopped and monitored on nodes of the cluster.

1. The resource type for Sun Cluster HA for nfs is SUNW.nfs
2. The resource type for Sun Cluster HA for apache is SUNW.apache

DRL - Veritas Volume Manager

DRL - Dirty Region Logging:

The method by which the VxVM monitors and logs modifications to a plex as a bitmap of changed regions. For a volumes with a new-style DCO volume, the DRL is maintained in the DCO (Data Change Object) volume.

How does it works?
DRL logically divides a volume into a set of consecutive regions and keeps
track of the regions to which
writes occur. A log is maintained that contains a status bit representing each
region of the volume. For any write operation to the volume, the regions being
written are marked dirty in the log before the data is written.

If a write causes a log region to become dirty when it was previously clean
the log is synchronously written to disk before the write operation can occur.
On system restart, VxVM recovers only those regions of the volume that are
marked as dirty in the dirty region log.