The Geek Diary

What are different Oracle Database Vault Roles

Thu, 21 Jan 2021 13:04:19 GMT

Oracle recommends that you do not use these top-level accounts for regular administration tasks; instead, you should give the DV_OWNER and DV_ACCTMGR role to individual administrators who secure them with their own password. If the top-level passwords were forgotten, you could no longer enable or disable Database Vault. This course uses LEO_DVOWNER and BEA_ACCTMGR as […]

Unable to export realm protected table using data pump

Thu, 21 Jan 2021 12:35:47 GMT

A database user cannot export with expdp if an object is protected by a realm due. This post is intended to explain the fix for this bug and the steps to implement before doing an export or an import using data pump (expdp / impdp) if Database Vault is enabled. A user can use data […]

Beginners Guide to Oracle Database Vault

Thu, 21 Jan 2021 11:53:30 GMT

Oracle Database Vault Concepts and Overview Oracle Database Vault enables organizations to transparently increase security without making changes to their application code. Oracle Database Vault provides real-time preventive controls by restricting access to application data from highly privileged users. Oracle Database Vault helps organizations address regulatory compliance, industrial espionage, and insider threats while at the […]

How to Disable IPv6 on Ubuntu 18.04 Bionic Beaver Linux

Mon, 11 Jan 2021 11:59:05 GMT

Ubuntu 18.04 Bionic Beaver Linux enables Internet Protocol Version 6 (IPv6) by default. However, in certain situations, some users may find it desirable to disable IPv6 support or to re-enable it after it has been disabled. Disabling IPv6 support (Permanently) Disable ipv6 built-in kernel module. 1. Edit /etc/default/grub and append ipv6.disable=1 to GRUB_CMDLINE_LINUX and GRUB_CMDLINE_LINUX_DEFAULT […]

How to Capture More Logs in /var/log/dmesg for CentOS/RHEL

Sat, 09 Jan 2021 02:36:58 GMT

Sometimes not all log messages in /var/log/dmesg can be captured after Linux OS/kernel boots up because of too many block devices attached to the server. This post illustrates another way to record all bootup log messages besides configuring the serial console. Basically kernel parameter “log_buf_len” can be configured to increase kernel log buffer size, Name: […]

Unable to Start RDMA Services on CentOS/RHEL 7

Wed, 06 Jan 2021 11:37:16 GMT

The Problem The RDMA service fails to start on CentOS/RHEL 7 machine. ‘journalctl -r’ command shows the below errors: Oct 11 11:01:15 geeklab systemd-modules-load: Failed to insert 'rds_rdma': Address family not supported by protocol Oct 11 11:01:15 geeklab systemd-modules-load: Failed to insert 'rds_rdma': Address family not supported by protocol Oct 11 11:01:15 geeklab systemd-modules-load: Failed […]

How to rename a KVM VM with virsh

Wed, 06 Jan 2021 11:23:34 GMT

The syntax is to rename a KVM VM with virsh is as follows: # virsh domrename {domain} {new-name} Let’s see an example of renaming a VM using virsh. 1. To rename VM from serverA to serverB, first shutdown the VM: # virsh shutdown serverA 2. Now to rename a VM, run: # virsh domrename serverA […]

How To Create "A CRS Managed” ACFS FileSystem On Oracle RAC Cluster (ASM/ACFS 11.2)

Tue, 15 Dec 2020 12:56:20 GMT

1. Create the mount points on all the nodes (as root user): # mkdir /goldengate 2. Connect to the ASM instance & create the ACFS diskgroup (from the +ASM1 instance): SQL> CREATE DISKGROUP ACFSTEST EXTERNAL REDUNDANCY DISK 'ORCL:ASMDISK18' SIZE 4157 M DISK 'ORCL:ASMDISK19' SIZE 4157 M ATTRIBUTE 'compatible.asm' = '11.2', 'compatible.advm' = '11.2'; Diskgroup created. […]

How to Check Storage Type in Engine Database (OLVM)

Fri, 11 Dec 2020 15:06:26 GMT

This is a small how-to post to check the storage type in Engine Database. Table storage_server_connections has all connections information. Run below command on OLVM to get the connection information: $ /usr/share/ovirt-engine/dbscripts/engine-psql.sh -c "select connection,iqn,port,storage_type from storage_server_connections;" connection | iqn | port | storage_type ------------------------------+-----+------+-------------- The field storage_type will give: value 1 for NFS value […]

How to set "max_report_luns” and "max_luns” on CentOS/RHEL 7 to scan more than ...

Fri, 11 Dec 2020 05:55:03 GMT

From CentOS/RHEL 7, the default value of parameter max_report_luns has been increased from 512 to 16383. Consequently, CentOS/RHEL 7.x can now discover more than 511 LUNs when the system scans the SCSI interconnect using the Report LUNs mechanism. Increasing this value beyond 16383 is generally not required. But if you want to increase it, then […]

How to set "max_report_luns” and "max_luns” on CentOS/RHEL 6 to scan more than ...

Thu, 10 Dec 2020 13:47:02 GMT

The default limit of maximum luns that can be presented in a CentOS/RHEL 6 is 512. But in many cases, you may want to increase this limit. There is a parameter of the SCSI core module to control the number of multiple LUNs. View Current Settings To view the current setting of “max_luns” parameter, use […]

How to Check the Size og yum Channels in CentOS/RHEL

Thu, 10 Dec 2020 13:18:47 GMT

Question: How to find out how large a yum channel repository is, to know how much data the channel will sync to a local yum repository? To see the actual size of the repository use either the ‘yum repolist -v‘ or ‘yum repoinfo‘ command. Example for checking the size of “CentOS-8 – AppStream” yum channel […]

How to Check vendor of installed RPM packages in Linux

Thu, 10 Dec 2020 04:18:20 GMT

This is a quick how-to post on checking the vendor of the installed rpms on a system. In some scenarios, a custom rpm package may not be compatible or supported on the specific system or environment. This post will help you identify the vendor of rpm which are either thrid party or not native to […]

TimeFinder SnapVX Concepts and SnapVX Operations

Sun, 06 Dec 2020 15:13:37 GMT

TimeFinder SnapVX Overview TimeFinder SnapVX provides a highly efficient mechanism for taking periodic point-in-time copies of source data without the need for target devices. Target devices are required only for presenting the point-in-time data to another host. Sharing allocations between multiple snapshots makes it highly space-efficient. A write to the source volume will only require […]

Repairing filesystem issues at Boot in CentOS/RHEL 7 and 8

Tue, 01 Dec 2020 19:44:17 GMT

This post focuses on manually repairing the file-system configuration or corruption issues that stop the boot process. Diagnosing and fixing file system issues Errors in /etc/fstab and corrupt file systems can stop a system from booting. In most cases, systemd drops to an emergency repair shell that requires the root password. The following table lists […]

How to Use Udev Rules to Create oracleasm Disks in CentOS/RHEL 8

Mon, 30 Nov 2020 07:10:28 GMT

This post will help to configure Oracleasm disks using Udev rules in 2 node cluster. On first node 1. List the disks: [root@node01 ~]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sda 8:0 0 2G 0 disk sdb 8:16 0 2G 0 disk Note: Create partitions for the disks. 2. Find the disk ID: […]

How to Configure an NFSv4-only Client using nfsconf in CentOS/RHEL 8

Thu, 19 Nov 2020 03:13:11 GMT

The nfsconf tool CentOS/RHEL 8 introduces the nfsconf tool to manage the NFS client and server configuration files under NFSv4 and NFSv3. Configure the nfsconf tool using /etc/nfs.conf (the /etc/sysconfig/nfs file from earlier versions of the operating system is deprecated now). Use the nfsconf tool to get, set, or unset NFS configuration parameters. The /etc/nfs.conf configuration […]

How to Schedule Tasks Using at in Linux

Fri, 06 Nov 2020 09:52:11 GMT

The atd Daemon The atd daemon allows users to submit jobs to be performed at a later time, such as “at 2:00am”. In order to use the atd daemon, it must be running. Users can confirm that atd is running simply by examining a list of running processes: $ ps aux | grep atd daemon […]

Beginners Guide to Tuning Profiles in CentOS/RHEL

Mon, 26 Oct 2020 09:01:15 GMT

Tuning Systems System administrators can optimize the performance of a system by adjusting various device settings based on a variety of use case workloads. The tuned daemon applies tuning adjustments both statically and dynamically, using tuning profiles that reflect particular workload requirements. Configuring Static Tuning The tuned daemon applies system settings when the service starts […]

How to use ansible-config to discover and investigate configuration options

Fri, 23 Oct 2020 12:08:40 GMT

Viewing Configuration Options If you want to find out what options are available in the configuration file, use the ansible-config list command. It will display an exhaustive list of the available configuration options and their default settings. This list may vary depending on the version of Ansible that you have installed and whether you have […]