Increase or Decrease LV Swap in CentOS 6/RHEL 6

Scenario: How to increase or decrease swap space(logical volume swap) in CentOS 6/RHEL 6

System: CentOS 6/ RHEL 6

Steps increase Swap space
Example increase 1 GB swap space.

1) You must check the path of swap logical volume and the free space in the swap volume group before continue to step 2.
# free -m
# lvdisplay | grep swap
# vgs

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Fixing Postfix error unknown user name value: nobody

System: RHEL 6.9

Just got complain from App support Postfix was error.
Check on /var/log/maillog show this error
postfix[2319]: fatal: file /etc/postfix/main.cf: parameter default_privs: unknown user name value: nobody

The solution I did,check on /etc/passwd and found the user nobody in comment state.
Uncomment nobody and Postfix can start again.

# vi /etc/passwd
Uncomment nobody

# service postfix restart

Install VMware-tools on CentOS 6

Scenario: Install VMware-tools CentOS 6 on VMware ESXi 6

Steps:
– Right click on guest VM.
– Select Install/Upgrade VMware Tools. Note: VMware tools installer will assign as CD/DVD or iso image in the server.
– Login as root access the server or SSH remote to install VMware tools.
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Extend Logical Volume size on RHEL/CentOS 6

Scenario:
Extend/Growing Logical Volume size for /opt on RHEL/CentOS 6.

Login as root then follow below steps:
1) Check free size in Volume Group (VolGroup).If still there free size then continue to step-2.
# vgs

[root@VTEST01 ~]# vgs
  VG       #PV #LV #SN Attr   VSize  VFree
  VolGroup   2   7   0 wz--n- 59.50g 12.00g
[root@VIDHOLXDTESTAP01 ~]#

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Added New VMware Disk and Mount to new Directory on CentOS 6

Scenario:
Added new 10GB VMware Hard Disk,create new Volume Group(Vgs),Create new LVM,format to ext4 and mount to /data

Steps in VMware vSphere:
– Right click on VM -> Select Edit Settings… -> Click Add... -> on Device Type select Hard Disk -> Click Next
– Select Create a new virtual disk -> Click Next
– Specify disk size (this scenario is 10GB), select default Thick Provision Lazy Zeroed then specify the disk location (default is Store with virtual machine) -> Click Next
– Specify Virtual Device Node (default for 2nd Hard disk will be SCSI (0:1), on Mode box leave blank -> Click Next
– Click Finish.
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Distribute Google Chrome via GPO


System: Windows Server 2008 R2

First download Google Chrome .msi installer from here and ADM/ADMX package from here.

Create a Distribution Point
To publish or assign a computer program, you must create a distribution point on the publishing server which a shared network folder where you will put the Google Chrome msi file that you want to distribute.

Note: This share must be accessible by your client machine. The client machine will request the file from this location. Verify the share is working correctly and set permissions on the share to allow access to the distribution package
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Connect to MikroTik which using Dynamic Public Ip Address


Starting from RouterOS version 6.14, MikroTik offers a Dynamic DNS name service with some clicks on WinBox we can connect to MikroTik device which using dynamic public ip address from internet.

System: RB750 v6.2x

Steps to setup IP Cloud:
1) Login to Mikrotik via WinBox as Administrative priviledge.
2) On IP menu select Cloud
setupMktIPCloud1
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WordPress admin site not found

I was late approx 1 month to renew the domain then when I need to access WordPress admin page redirect to “not found,this is embarassing bla bla bla…”

Here My solution:
– Login to Cpanel -> File Manager -> go to your WordPress folder (usually under public html folder)
– Check the permission of wp-login.php. In my case while can not access the admin site the permission was 000, I change the permission of wp-login.php to 500 then problem solved, admin site can access back to normal.

Another usefull tips from WordPress codex if can not access WordPress admin page issue go here