Dev {Tricks}

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Fix read only fstab

  • “/ etc/fstab” [readonly]
  • can’t edit fstab read only
  • file ‘/ etc/fstab’ is unwritable
  • Repairing fstab (read only /)

If / etc/fstab is correct, you can simply type:

mount -n -o remount /

But if / etc/fstab is wrong, the device name and possibly the type must have to be given too: e.g.

mount -n -o remount -t extX /dev/sdaX /

Where,
extX is your filesystem type
/dev/sdaX is the partition you want to mount

To see all your available partitions just type ls /dev/[sh]d*.

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MySQL database table “in use” problem

  • MySQL table collation suddenly changed to “in use”
  • Unable to login, registration, reset password

Backup database.

Error occurs when you set the connection collation to anything other then the current server collation.

So

  • Repair database (repairing database will fix the “in use” issue)
  • Then change the collation to same everywhere.
  • You may also check the collation in the config file.

That’s all!

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Changing the partition layout of your VPS and VDS after installation | Linux

  • How to easily change your partition layout on your VPS or VDS.

Backup of all important data before proceeding! Changes to the partition table always bear the risk of complete data loss.

  • Boot your VPS / VDS into the rescue-system
  • Now connect through VNC (How to use VNC to connect to your VPS and VDS)
  • Login as “root”
  • To perform changes on the partition easily use gparted
  • To start the GUI type “startxfce4” within VNC console and wait a few seconds until the graphical interface appears
  • On the upper left side you will see “Applications”, open it and select “Run Program”
  • Type “gparted” within the application finder and the app should start immediately
  • Now you can resize and create new partition with unallocated space.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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How to increase memory limit?

  • Fatal error: Allowed memory size of 123456 bytes exhausted (tried to allocate 234567 bytes) in /path/file.php

Usually your php.ini will be located at (XX – PHP version, for example 73):

vi /usr/local/php73/lib/php.ini

or use below trick to find your php.ini would be to ask php itself what it’s using, eg:

/usr/local/bin/php --ini | grep 'Loaded Configuration File'

or another trick to find php.ini

php -i | grep "php.ini"

Now open the php.ini file and edit memory_limit to a higher value.

memory_limit = 8M      ; Maximum amount of memory a script may consume (8MB)

Save, and then restart apache.

systemctl start httpd.service

CentOS/RHEL (Red Hat) Linux version 7.x or newer specific commands

or

sudo systemctl restart httpd.service

Alternative way: php.ini per folder

Location of the global server php.ini file is

/usr/local/php/php.ini

Location of the global per account php.ini file is

/home/USERNAME/php.ini

You can also have per folder changes, example:

/home/USERNAME/public_html/website1.com/php.ini
/home/USERNAME/public_html/website2.com/php.ini
/home/USERNAME/public_html/website2.com/myapp/php.ini

How to test php.ini changes?
Simple create phpinfo.php file in the users public_html folder and add the following content in it.

Example location: /home/USERNAME/public_html/phpinfo.php

<?php
phpinfo();
?>

Now open url in your browser (Apache restart is NOT needed):

http://your-domain.com/phpinfo.php

PHP.ini values

http://php.net/manual/en/ini.list.php

 

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Restart an Apache Web Server

Using Init.d

/etc/init.d/apache2 restart
sudo /etc/init.d/apache2 restart
sudo service apache2 restart

For a graceful restart, replace restart with reload.

For CentOS and RHEL servers

service httpd restart

Using Systemctl

systemctl restart apache2.service

Using Apachectl

sudo apachectl -k restart
sudo apachectl -k graceful