Question: Given an LVM partition, how can we extend it to give some addtional space? Swap filesystem Swap is used if there is not enough memory available for your application. It's normal and can be a good thing for Linux systems to use swap, even if there is still available RAM. But, it's not just used if there is not enough memory. How to extend LVM based swap filesystem To increase the space for LVM Swap partition follow the steps given below: 1. Verify availability of the new … [Read more...] about How to extend an LVM swap partition in Linux
How to install packages using dnf in CentOS/RHEL 8
CentOS/RHEL has a new package manager called DNF which can be used to install packages on CentOS/RHEL 8 systems. DNF or Dandified YUM is the next-generation version of the Yellowdog Updater Modified (yum), a package manager for rpm-based distributions in CentOS/RHEL 8. It also resolves dependencies automatically. The following is an example of how to use DNF to check which repositories are enabled and to then install a package from an enabled repository. 1. To check the list of … [Read more...] about How to install packages using dnf in CentOS/RHEL 8
How to list all modules and check if they are enabled or disabled in CentOS/RHEL 8
CentOS/RHEL 8 distributes sets of related RPM packages that form a logical unit (such as different components of an application or a group of tools) as modules, with these modules being able to be enabled or disabled on the system. How can a user or administrator of an OL8 system determine what modules are installed or are enabled or disabled on their system? Modules a set of RPM packages that are grouped together and must be installed together. They can contain several streams (AppStreams) … [Read more...] about How to list all modules and check if they are enabled or disabled in CentOS/RHEL 8
How To Migrate Existing Iptables rules to Nftables In CentOS/RHEL 8
In CentOS/RHEL 8, the default iptables network packet filtering framework been replaced with the nftables framework. As the designated successor to iptables, ip6tables, arptables, and ebtables, the nftables framework includes packet classification facilities and several improvements, which provide added convenience and improved performance over the previously used packet-filtering tools. In this post we will discuss on how to migrate existing iptables rules to nftables in CentOS/RHEL … [Read more...] about How To Migrate Existing Iptables rules to Nftables In CentOS/RHEL 8
How to Configure Existing Lvm Volume Group to Use DM-Multipath
Question: PV called "/dev/sdb" that was created over a single device path, need to set this PV to have effective multipath functionalities (Migration of PV from single path to multipath names) How to configure existing lvm volume group to use DM-Multipath? It is required to use the existing Volume Group and the existing Logical Volume configuration to ensure that the server-side configuration does not cause any referencing problems for any underlying application (mount points, … [Read more...] about How to Configure Existing Lvm Volume Group to Use DM-Multipath
How to convert NON-OMF to OMF files ( Oracle Managed File conversion – NON-ASM )
1. Who Can Use Oracle Managed Files? Oracle Managed Files are most useful for the following types of databases: A logical volume manager that supports striping/RAID and dynamically extensible logical volumes. A file system that provides large, extensible files Low end or test databases. Initialization Parameters That Enable Oracle Managed Files for Datafiles, Redo and Controlfiles: DB_CREATE_FILE_DEST DB_CREATE_ONLINE_LOG_DEST_n DB_RECOVERY_FILE_DEST The name that is used for … [Read more...] about How to convert NON-OMF to OMF files ( Oracle Managed File conversion – NON-ASM )
ORA-28007: the password cannot be reused
The Problem You attempt to alter a user's password to a previously used one and get the following error when attempting to reuse the old password: SQL> alter user med identified by med * ERROR at line 1: ORA-28007: the password cannot be reused The password 'med' has been assigned to this user previously. The Solution The user is assigned a profile that defines the number of changes required before a password can be reused. The parameter in the profile is the limit … [Read more...] about ORA-28007: the password cannot be reused
Beginners Guide to Oracle Password Management Policy
Overview Password Management is setup by DBAs using Oracle Profiles. A general recommendation is to assign only those schemas a profile with password aging and expiration features if the users have the ability to independently change their password from their end-user application when the password expires, usually, this means the application they use must have correctly implemented the OCIPasswordChange() OCI call such as sqlplus. A Profile is setup with the required password parameters and … [Read more...] about Beginners Guide to Oracle Password Management Policy
How to List Tables Per Tablespace In MySQL Cluster
Question: How to list tables inside tablespaces in a MuSQL cluster? The following query meets the aim of the question, lists the database, table name and the corresponding tablespace: SELECT DISTINCT t.table_schema, t.table_name, p.tablespace_name FROM partitions p JOIN TABLES t ON (t.table_schema=p.table_schema and t.table_name = p.table_name) WHERE t.engine='ndbcluster' and tablespace_name IS NOT NULL … [Read more...] about How to List Tables Per Tablespace In MySQL Cluster
Understanding Device Persistence and Oracle ASMLib
Basics This post describes some advantages the Linux specific ASM library provided by Oracle (herein "ASMLib") brings to the administration of a Linux system running Oracle. Linux often presents the challenge of disk name persistence. Change the storage configuration and a disk that appeared as /dev/sdg yesterday can appear as /dev/sdh after a reboot today. How can these changes be isolated so that they do not affect ASM? Why Not Let ASM Scan All Disks? ASM scans all disks it is allowed to … [Read more...] about Understanding Device Persistence and Oracle ASMLib