master-slave replication in MySQL

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Looking for some help configuring 5.0.45 master-slave replication. Here's my scenario...

We have a heavily loaded 30gb 5.0.45 DB we need to replicate via master-slave configuration to a new, beefier server running same mysql 5.0.45, and then cutover to the new server. Due to extreme SAN congestion and a grossly overloaded master server, our DB dumps take 5.5 hours. But we cannot afford that much downtime or locking during the replication transition; we can manage 10-15 minutes, but more is very problematic.

I understand that "FLUSH TABLES WITH READ LOCK" will lock the tables for the duration of the 5.5 hour dump. Is this true?

If so, we'd like to dump/initialize/sync slave WITHOUT any locking anything the master for more than a few seconds if at all possible. Will this give us the dump we need?

 mysqldump --single-transaction --master-data --all-databases

posted Aug 28, 2013 by Sanketi Garg

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Why don't u try snapshot backups, where the lock held for less duration. Or can't u take mysql dumps during Night time when there is less bd activity

commented Aug 28, 2013 by Deepak Dasgupta

I neglected to mention these systems are both CentOS linux systems. Unfortunately, the 5.5 hour dumps are already done during the least busy times.

Regarding snapshots, how long are snapshot locks held? These are ext4 filesystems. Assuming the lock is not held for long, what's the recommended way to do snapshots on ext4?

commented Aug 28, 2013 by anonymous

1 Answer

If u have LVM's then lock is held only for the duration of taking snapshot, which would be few min, if there is very less activity on the db.

answer Aug 28, 2013 by Deepak Dasgupta

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