In previous post, I mentioned setting of the emcli and resolving of SSL problem. In this post, I will show you how we simply backup using RMAN through emcli. It is necessary to login  successfully to OMS to backup your database. And all necessary privileges should be given to user who logins to OMS. Creating a Property file: First… Continue reading

Hello Folks, The last week one of our customer wanted to automate their Oracle backup systems. As an Oracle environment, customer has Oracle 12c. Luckily Oracle 12c designed for the Cloud. Oracle Enterprise Manager is the graphical interface for managing all of  Oracle database environment. Oracle Enterprise Manager has also command line interface which we… Continue reading

What is PxE ? PxE is a way of booting OS kernel over the network rather than from disk. It consist of one or more PxE servers which holds all kernel and initial ramdisk image. And PxE clients which are actual host where user application and services start. It is depicted in the Figure-1. PxE… Continue reading

This is the last part of clustering series post regarding Red Hat HA cluster. In this post, HA NFS will be created in the cluster. Creating a Fail-over Domain Creating Resources. As you see the section nfs client we specify the target *(all). It is not secure configuration, so you should specify network addresses that you… Continue reading

In this post, we will do the actual work to finish cluster configuration such as starting cluster services, configuration of the clustered LVM disk, creating Fail-over domain, resources, and service groups. Two-Node Cluster As it is indicated in the previous posts two-node cluster is a special form of a cluster because of split-brain situations. So we will add special… Continue reading

In the previous post, we prepared cluster environment such as cluster nodes(2), disks(3) network interfaces on each node(2)  and installed necessary packages on the nodes to build our cluster. In this part, we start building our cluster environment. Creating Quorum Disk We need to initialize one of our three disks as a quorum disk which is /dev/sdb in this… Continue reading

Creating CA Certificate We use this certificate for only signing certificates that we use for the clients and our web servers. It should be kept very secure. If it is disclosed other certificates signed with this certificate will be disclosed as well. Creating a Key and CSR for the Client Creating a client certificate is… Continue reading

Sometimes we need to crash the system for testing of cluster  fencing functionality  and fail-over functionality.  Actually in Linux we can create a fake kernel panic by issuing below commands.   Will perform a system crash by a NULL pointer dereference. A crash dump will be taken if configured. Reference:https://www.kernel.org/doc/html/v4.11/admin-guide/sysrq.html Continue reading