Apr 10 2015

How to Delete psql Command Prompt History in PostgreSQL

Category: AdministrationFatih Acar @ 09:56

When you use psql command prompt, system automaticly saves your prompts. If you use password when user creates operation, this situation can occur security risk. Therefore, you can delete this prompts with editing psql_history file like below.

Find And Delete psql Prompts

[root@pg ~]# locate .psql_history
/var/lib/pgsql/.psql_history
[root@pg ~]# vi /var/lib/pgsql/.psql_history

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Tags: PostgreSQL, PostgreSQL Administration


Mar 25 2015

How to Change SSH Port When Selinux is Enable on Oracle Linux 7

Category: Linux & Unix,System SecurityFatih Acar @ 15:47

SSH service runs on 22 port number. You can change this port number for security. If you use Oracle Linux 7, Centos 7 or Red Hat Linux 7 versions, you can change port number with below operations. If selinux is enabled, you have to add new port number to selinux configuration because of the fact that selinux allows only 22 port number for ssh connections.

Step 1 : Change Port Number

[root #] vi /etc/ssh/sshd_config
Port 2290

Save and Exit

Step 2 : Change Selinux Configuration

To change:
[root #] semanage port -a -t ssh_port_t -p tcp 2290
To list:
[root #] semanage port -l | grep ssh

Step 3 : Restart SSHD Service to Activate New Confiuration

[root #] systemctl restart sshd.service

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Mar 09 2015

Oracle Cluster Service Control Commands CRSCTL

Category: AdministrationFatih Acar @ 09:54

crsctl is Oracle Clusterware management command. You can check, start, stop clusterware with crsctl. crsctl command directory is $GRID_HOME/bin.

You can do below operations with crsctl

  • Starting and stopping Oracle Clusterware resources
  • Enabling and disabling Oracle Clusterware daemons
  • Checking the health of the cluster
  • Managing resources that represent third-party applications
  • Integrating Intelligent Platform Management Interface (IPMI) with Oracle Clusterware to provide failure isolation support and to ensure cluster integrity
  • Debugging Oracle Clusterware components

List Status Of All Crs Services

crs_stat -t

Continue reading “Oracle Cluster Service Control Commands CRSCTL”

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Tags: crsctl, Oracle, Oracle Administration, Oracle Cluster Management


Feb 18 2015

Linux Logical Volume Manager Configuration And Extend Disk Operation

Category: Linux & UnixFatih Acar @ 11:38

Logical Volume Manager is a disk partitioning solution on linux systems. This architecture provides advantages. You can extend disk size easyly with lvm without losing exist data. But, If you use fdisk that is classical method for partition, you can not resize this partitions without losing data.

You can follow below steps to configure lvm.

LVM Creation Steps

1- Disk partition “cfdisk”
2- Create physical volume “pvcreate”
3- Create virtual group “vgcreate”
4- Create logical volume “lvcreate”
5- Format logical volume “mkfs.ext4″
6- Add Fstab “vi /etc/fstab”

LVM Architecture

Logical Volume Manager Architecture

Logical Volume Manager Architecture

Configure LVM Disks
Continue reading “Linux Logical Volume Manager Configuration And Extend Disk Operation”

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Feb 12 2015

Fstab Cannot Writable

Category: Linux & UnixFatih Acar @ 09:41

If you mount disk with wrong uuid or wrong text in fstab file, you get an error when system restart. Your system can not open. If you want to change fstab, you can not change this file because of read only. You can change this status with “mount -o remount,rw /” command. This command provides that system takes maintenance mode. /etc/ directory’s below files will be writable.

Error

fstab1

Solution
Continue reading “Fstab Cannot Writable”

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Tags: fstab, Linux Administration, Linux Error and Solution, Oracle Linux, System Administration


Jan 27 2015

How to Change Oracle Enterprise Manager Port Number

Category: Administration,Database SecurityFatih Acar @ 17:29

If you want to change Oracle Enterprise Manager port number, you can use “emca -reconfig ports -DBCONTROL_HTTP_PORT ” command, this is simple. You can use to take security measure for Oracle EM. I will give 1820 as port for Oracle EM as example.

Change Oracle Enterprise Manager Port

change-oracle-enterprise-manager-port

Continue reading “How to Change Oracle Enterprise Manager Port Number”

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Tags: Database Administration, Database Security, Oracle Administration, Oracle Security


Dec 23 2014

RMAN Encrypt Backup in Oracle

Category: Backup And Recovery,Database SecurityFatih Acar @ 09:04

You can protect your backups with rman encryption. You have three ways to rman backup encryption. You can use wallet, password or dual mode. I will tell you password protection.

Configure RMAN Backups With Password Protection

rman target /
RMAN> set encryption on identified by ‘yourpassword’ only;

You can backup with backup database command. Do not need to change any backup script.

You can change encryption algorithm on RMAN Configuration.

Show Encryption Algorithm

SQL> select algorithm_id, algorithm_name, algorithm_description, is_default from v$rman_encryption_algorithms;

Change Encryption Algorithm
Continue reading “RMAN Encrypt Backup in Oracle”

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Tags: Database Administration, Database Security, Oracle Administration, Oracle Backup and Restore, RMAN Encrypt Backup


Dec 22 2014

How to Create Oracle Wallet for Encrpytion

Category: Administration,Database SecurityFatih Acar @ 14:35

Oracle Wallet Manager is a password protected stand-alone Java application tool used to maintain security credentials and store SSL related information such as authentication and signing credentials, private keys, certificates, and trusted certificates.

1- Create Wallet Directory

[oracle@testdb ~] cd $ORACLE_HOME
[oracle@testdb db_home] mkdir -p ORA_WALLETS

2- Write Wallet Location Information in sqlnet.ora File

[oracle@testdb ~] cd $ORACLE_HOME/network/admin
[oracle@testdb db_home] vi sqlnet.ora

oracle_wallet_sqlnetora

3- Configure Wallet in Oracle Database
Continue reading “How to Create Oracle Wallet for Encrpytion”

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Tags: Database Administration, Database Security, Oracle Administration, Oracle Security, Oracle Wallet


Dec 20 2014

How to Move Datafile to Different Directory in Oracle

Category: Administration,Backup And RecoveryFatih Acar @ 15:23

You can move datafiles to different directory. You have to make offline tablespace or take mount mode database to change datafiles location. System, temporary and rollback tablespace can move only when database is mount mode.

Show Tablespaces And Datafiles With Locations

SQL> select tablespace_name, file_name from dba_data_files;

Change Location Of Normal Datafile

SQL> alter tablespace TS_TEST offline;
[oracle@testdb oradata] mv /oradata/ts_test01.dbf to /oradata2/
SQL> alter tablespace TS_TEST rename datafile ‘/oradata/ts_test01.dbf’ to ‘/oradata2/ts_test01.dbf';
SQL> alter tablespace online;

Task complated.

Change Location Of System, Temporary or Rollback Tablespace’s Datafiles
Continue reading “How to Move Datafile to Different Directory in Oracle”

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Tags: Database Administration, Oracle Administration, Oracle Backup and Restore


Dec 15 2014

Create DDL Views (RUTDDLSCREATE) Error While Restoring SAP PI

Category: Errors and SolutionsFatih Acar @ 19:52

I got an error while I was restoring SAP PI system. I solved this problem by applying kernel patch.

Error

rutddlscreate_error

Solution
Continue reading “Create DDL Views (RUTDDLSCREATE) Error While Restoring SAP PI”

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Tags: Create DDL Views Error, SAP Basis, Sap Errors and Solutions, Sap System Administration


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