Read Only File System After Upgrade from Ubuntu 14.10 to Ubuntu 15.04

I just upgrade a server from Ubuntu from 14.10 to Ubuntu 15.04. The server started okay and I was able to ssh in. However, the login prompt said that is was a “Read only file system”. This means that I wasn’t able to run any commands to fix the issue.

After a bit of searching, I found that the problem was that the UUID was incorrect in the /etc/fstab/

Before upgrading the fstab was:

UUID=18254707-08e8-494e-b456-938592928a5e /               ext4    errors=remount-ro 0       1

After upgrading the fstab was:

UUID=815063a9-c956-44a6-ab11-05e1d0bb3a58 /               ext4    errors=remount-ro 0       1

To fix the issue:

1) You need to find what the correct UUID is. You find this using the command:

ls -al /dev/disk/by-uuid/*

2) You need to boot into the server in recovery mode and edit the fstab.

I hope this helps someone

How to increase the max image upload size in WordPress

There are two variables which restrict the maximum media upload size to wordpress.  There are PHP variables.

upload_max_filesize
post_max_size

Assuming that you are using Ubuntu and Apache then you should create a .ini file in the conf.d directory. Don’t edit the default php.ini file because this is sometimes updated by the package maintainer and there is a chance that any changed you make to might be lost. So create a file called:

/etc/php5/apache2/conf.d/wordpress.ini

I wanted up be able to upload 30 megabyte files and so put:

upload_max_filesize = 30M
post_max_size = 30M

Then restart Apache:

apache2ctl restart

I hope this helps someone.

backuppc – gui downloading bin file – Ubuntu 14.04

I’ve just made a fresh install of backuppc on Ubuntu 14.04. However, when I visited the web interface then the browser just shows a bin file like this:

Opening_246

Having a bin file server from Apache (or any other web server) generally means there is a fault with the webserver and the script isn’t being parsed before it’s served.   A quick look at the Apache log files located at /var/log/apache2/error.log shows the problems:

unable to connect to cgi daemon after multiple tries: /usr/share/backuppc/cgi-bin/index.cgi

Apache2 isn’t parsing the file through a cgi script.  The Apache server doesn’t have the cgi module enabled.  You can enable an Apache module from the command line without editing any configurations.

sudo a2enmod cgid

Then restart apache2

sudo service apache2 restart

You should then have a working copy of backuppc.

How to set the memory limit for MySQL

There is no variables like memory_limit in MySQL my.cnf file – therefore you can’t explicitly set the memory limit for MySQL. You have to configure your my.cnf file based on a combination of variables. These then multiple together to form the MySQL memory limit.

key_buffer_size + (read_buffer_size + sort_buffer_size) * max_connections = K bytes of memory

I hope this help someone.