Author: root

“Well! We have just one!

Step 1: Open a terminal window

# su –  or # sudo -s

Step 2: Creation of the Storage File for the new swap file

Type the following command to create 512MB swap file (1024 * 512MB = 524288 block size):

# dd if=/dev/zero of=/swap bs=1024 count=524288

If you don’t want to have to reboot use the following commands:
(This is useful for debugging automout issue)

524288+0 records in
524288+0 records out
536870912 bytes (537 MB) copied, 3.23347 s, 354 MB/s

1. if=/dev/zero : Read from /dev/zero file. /dev/zero is a special file in that provides as many null characters to build storage file called /swap.
2. of=/swap : Read from /dev/zero write storage file to /swapf.
3. bs=1024 : Read and write 1024 BYTES bytes at a time.
4. Count=524288 : Copy only 523288 BLOCKS input blocks.

Step 3 : Secure the new created swap file

Setup the correct file permission:

# chown root:root /swap
# chmod 0600 /swap

A world-readable swap file is a huge local vulnerability.

Step 4: Set up a Centos 7 swap area

Type the following command to set up a Linux swap area in a file:

# mkswap /swap

Sample outputs:

Setting up swapspace version 1, size = 524284 KiB
no label, UUID=0e5e7c60-bbba-4089-a76c-2bb29c0f0839

Step 5: Enabling the swap file

Finally, activate /swap swap space immediately, enter:

# swapon /swapfile1

Step 6: Update /etc/fstab file

To activate /swap after CentOS 7 system reboot, add entry to /etc/fstab file. Open this file using a text editor such as nano:

# nano /etc/fstab

Copy & Paste the following line:

/swap none swap sw 0 0

Save and close the file.

Verify if your swap file is activated?

# free -m

total       used       free     shared    buffers     cached
Mem:          1876       1798         77          0        119       1440
-/+ buffers/cache:        237       1638
Swap:         4607          0       4607

Display swap usage summary

# swapon -s

Filename				Type		Size	Used	Priority
/dev/sda6                               partition	4194296	0	0
/swap                                   file		524280	0	0

Another option is to view /proc/meminfo file:

# less /proc/meminfo
# grep -i –color swap /proc/meminfo

SwapCached:        30748 kB
SwapTotal:       6291448 kB
SwapFree:        6154008 kB

Optional, test the new swap file:

# swapoff -a
# swapon -a

Enjoy!

We had a strange bug in OC 3.x! When adding a PDF link outside of the OC files structure on the same domain name?!

mod_sec = nothing in my log’s,

.htaccess NO LUCK HERE!

The fix! 

Just call your pdf file(s),  https / http ,.. link inside your image directory structure ! ,,… ,, just create the OC directory “/image/catalog/terms (Or any name), use filezilla to upload your PDF file.

The bottom line is that you cannot call a non-OC directory, Ex,.: public_html/yournamehere/download/

must be located inside the OC structure:

public_html/yournamehere/image/catalog/…

Enjoy!

Whether installing a new physical hard drive to a server or adding an additional disk to your cloud server or VPS, you’ll need to configure CentOS to be able to use it.

We’re going to assume the drive is connected, so first of all, we need to find it.

First of all, we need to know the naming convention your server is using for drives, and we can find this with the ‘df’ command.

[user@server ~] df
Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/vda2       24733776 2521604  20942668  11% /
/dev/vda1        1007512  203260    751824  22% /boot

The two lines above show that this particular server is using the vd* notation, but sd* is also used.  Here the primary drive, vda, has two partitions – vda1 and vda2.

We can now use the following command to find other disks:

[user@server ~] ls -1 /dev/[sv]d[a-z]
/dev/vda
/dev/vdb

We can see both our original disk, vda, and the new disk vdb.  Now to create a filesystem the new disk with the ‘mkfs.ext4’ utility.

[user@server ~] sudo mkfs.ext4 /dev/vdb

This will just take a few seconds.

To use the new disk we now need to mount it.  When you’ve decided where you want to mount the disk, first create that folder on your server.  We’re going to use ‘home2’ for our disk.

[user@server ~] sudo mkdir /home2

We can now mount the disk to that location:

[user@server ~] sudo mount /dev/vdb /home2

Revisiting the df command we can now see that the new disk is mounted.

[user@server ~] df
Filesystem     1K-blocks    Used Available Use% Mounted on
/dev/vda2       24733776 2521604  20942668  11% /
/dev/vda1        1007512  203260    751824  22% /boot
/dev/vdb        25000000     100  24999900   1% /home2

To ensure the disk is automatically mounted when the server is rebooted, we also need to add it to fstab.  Our preferred editor is ‘nano’ so we type

[user@server ~] sudo nano /etc/fstab

We add, to the end of the file, the line:

/dev/vdb /home2 ext4 defaults 0 0

Then CTRL + O to save and CTRL + X to exit.

The disk will now stay mounted after reboot and you can begin using it.