How to setup a loadbalancer with HAProxy in RedHat 7
You have many options to install and configure a loadbalancer in RedHat 7. One of the best options is HAPorxy. To setup HAProxy, you have to download related RPM file and then install it: Then, you have to make changes in config file (/etc/haproxy/haproxy.conf): in this sample we have 4 servers as below: Then you […]
Add New Disk to RedHat-based Linux without reboot
If you add a new disk to your OS, you won’t find this device in the device list (fdisk -l command). So you have two options to make it available: Reboot your machine Make the OS rescan all connected devices In operational environments, the first option is not considerable. So we have to choose the […]
Change the Character Set & Collation of a table
To change the Character Set and Collation of a field of a table you have to use this query: if the table contains data, you have to update that data as follow:
Rebuild and Reorganize all indexes within a database
If you want to REBUILD and REORGANIZE all your indexes in a database, you have to use this query: Rebuild: Reorganize:
Backup/Restore Progress
To see the progress of Backup or Restore process you can use this query:
Database Startup Error: Fatal NI connect error 12547
If you see Fatal NI connect error 12547 error in alert log file of a Database in the middle of startup, and the database process couldn’t find DB PARAMETER FILE and CONTROL FILE, you have to check permissions,owner and group of these files: The permission of these files have to be 6751. The group of […]
IMPDP Errors: ORA-02374, ORA-12899
If the Character set of source and destination database are not equal, you will see below errors in the impdp log file: to solve this error, you have to restore the structure of tables first after that, you have to create a table and fill it with information about columns with have CHAR or VARCHAR […]
Grid Infrastructure & Oracle Database 12c – Preinstallation tasks
To install Oracle Grid Infrastructure & Oracle Database on Oracle Linux 7, you need to prepare your OS. To do so, you have to follow these commands: First of all, you have to install required packages in the OS: then, you have to edit /etc/hosts file and add the appropariate record as bellow: you may […]