On 8/19/2010 12:03 PM, Mick wrote:
I use mysqldump to back up a database from a development environment and
upload it to a production environment.
A couple of days ago I was surprised to see that I was getting errors as soon
as I uploaded the backed up database to the production machine! I repeated
the backup (more in disbelief than anything else) but the error remained.
I spent a few minutes looking around and scratching my head as to what was
amiss with it, until eventually I noticed that the recent backup was smaller
than the previous version (it should have been bigger due to extra data that
has accumulated in the database). I had another final go in running the same
good ol' mysqldump command and this time it worked. The backup was a
reasonable size and the upload restored the application in the production
environment in a good working order.
Is there a right and a wrong way of backing up mysql? Did I do something
wrong? How should one verify that a back up is sound? (Imagine trying to
restore from that incomplete backup!)
mysqldump -A --single-transaction
That's usually the best way to backup if you have a single machine.
Without --single-transaction you may or may not get a proper backup when
using Innodb tables on a busy server.
However in a busy production environment it's usually best to use a
slave to do backups. Bringing LVM snapshots into the mix is also useful,
but you must lock and flush Mysql in order to get a correct snapshot
which makes it only an option on the slave.
kashani
