So, I have to check and come with a backup solution for a very busy mysql server (with tables over 5 GB). Due to resources constraints, they choose to set all tables with the MyISAM engine. Currently, they use a bash script with calls to mysqldump for every single table, and they use the command --lock-tables=false, because it is imperative for them to be always online, but I really think that's not working the way they intended.
My guessing is all their backups are inconsistent, since they don't lock all the tables, but one by one with every dump. Am I correct?
Also, the only non-locking solution I can think of is to make a slave replication to properly lock the tables and use mysqldump or XtraBackup. My concern with this is getting a hit on performance, since it'll be writing twice and both instances will have to run on the same machine. Is there any other alternative for a non locking solution for MyISAM ?