Hi, thanks for the reply.
Yes, I tried backing up from the shell using mysqldump. Due to the size of the database, it takes a long time to backup and also seems to create table locks while it is backup up which is not great as my website is then not usable during the backup process. What tends to happen is, maybe an hour or two after kicking off mysqldump, I receive a "segmentation fault" error message.
The database tables are a mixture of InnoDB (for referential integrity) and MyISAM. The total database size is approx 5.5GB with one table 2.5GB (14 million rows).
I'd like to be able to create a full backup, if at all possible, without creating table locks as I'd like the system to still be usable while the backup is running (consistency is not vitally important). I'm not sure why the segmentation fault occurs (which is my main issue) but I'm led to believe it might be something to do with InnoDB.