Ubuntu: Buffer I/O error on device sr0 logical block

Most of the time this error occurs that is a bad disk or a bad drive (or a bad cable).
Ubuntu 8.10 seams (from own experience and google) to be commonly affected by this.

You can try the following (I try them in this order)

  • If you only get buffer errors and no CRC errors, just try and wait (a few minutes) It might still be possible to install
  • Try another installation CD [from the same installation image] – if this works, then the other disk is bad
  • Try to swap out the cable to the drive (if you have a ribbon cable use one with 80 connectors, not one with 40)
  • Try to swap out the drive
  • Try another installation CD [from another installation image, old version, other dist, windows] – if this works then there is an issue with the installation image – there might be an issue worth reporting

If all this fails or you wish to install the version you have, then using a usb stick to install the image might be a good idea.

Magento: Installing on a debian server

To install magento on a fresh server use the following.

  • Install apache, mysql and PHP5 “$ apt-get install apache2 mysql-server php5 php5-mysql php-soap php5-mcrypt php5-curl php5-gd”
  • Edit the vhost config for the apache site [/etc/apache2/sites-enabled/000-default]
    • Verify that “AllowOverride” is set to All for the magento directory
  • Make sure that mof_rewrite is loaded; use “$ a2enmod rewrite” and then reload apache2
  • Edit /etc/php5/apache2/php.ini
    • “memory_limit” [the manual says] no less than 256Mb (preferably 512)
    • “max_execution_time” [this is the max time that a script may be left running] SOAP requests take time, so make suer it is at a reasonable time
    • “upload_max_filesize” Set this to a size that is reasonable depending on what you plan to upload (manuals might be large)
    • “post_max_size” Set this to a size that is reasonable depending on what you plan to post (manuals might be large); also make sure that the value and the modifier is correct (so that it says 8M and not just 8 for instance)
    • “display_errors” Set to Off
    • “log_errors” Set to On
    • “error_log” Set to a file that you will be able to find [if you wish to have it in a subdir; create that as root and give it permissions as apache log dir]
  • download magento (lastest version from magento
  • Upack it (I choose bzip2 format) “$ tar -jxvvf magento-downloader-” and make sure the files gets put in the directory you wish
  • Some directories have to be writable to the webserver (and all subdirectories, where there are)
    • var
    • var/.htaccess
    • app/etc
    • media
  • If you are using the downloader installation
    • “$./pear mage-setup .”
    • “$./pear install magento-core/Mage_All_Latest”
    • “$rm -rf downloader/pearlib/cache/* downloader/pearlib/download/*”
  • Create database and database user [this is to do it manually via mysql console]
    • “$mysql -uroot -p”
    • “mysql> create database magento;”
    • “mysql> use mysql;”
    • “mysql> INSERT INTO user (Host,User,Password) VALUES (‘localhost’, ‘magento’, PASSWORD(‘password’));”
    • “mysql> GRANT ALL ON magento.* TO ‘magento’;”
    • “mysql> FLUSH PRIVILEGES;”
    • “mysql> exit”
  • Go to the webserver and complete the installation
  • If you get stuck on the configuration page [that you get back to it even after adding correct information]:
    • Check “AllowOverride” in the apache config.
    • Check “post_max_size2 in the php.ini [also check so that the value is either absolute or has a modifier; 8 means 8 bytes while 8M means 8Mb]