I wrote couple of weeks ago on dangers of bad cache design. Today I’ve been troubleshooting the production down case which had fair amount of issues related to how cache was used. The deal was as following. The update to the codebase was performed and it caused performance issues, so it was rolled back but [...]
MongoDB Approach to database synchronization
April 30, 2010 By 5 Comments
I went to MongoSF today – quite an event, and I hope to have a chance to write more about it. This post is about one replication problem and how MongoDB solves it. If you’re using MySQL Replication when your master goes down it is possible for some writes to be executed on the master, [...]
Just how useful are binary logs for incremental backups?
July 21, 2009 By 6 Comments
We’ve written about replication slaves lagging behind masters before, but one of the other side effects of the binary log being serialized, is that it also limits the effectiveness of using it for incremental backup. Let me make up some numbers for the purposes of this example: We have 2 Servers in a Master-Slave topology. [...]
Faster MySQL failover with SELECT mirroring
February 1, 2009 By 9 Comments
One of my favorite MySQL configurations for high availability is master-master replication, which is just like normal master-slave replication except that you can fail over in both directions. Aside from MySQL Cluster, which is more special-purpose, this is probably the best general-purpose way to get fast failover and a bunch of other benefits (non-blocking ALTER [...]
Can MySQL temporary tables be made safe for statement-based replication?
May 26, 2008 By 8 Comments
A while ago I wrote about how to make MySQL replication reliable, part of which is to eliminate temporary tables. The idea is this: if a slave is stopped (or crashed) while a temporary table is open and is then restarted, the temporary table doesn’t exist anymore, and the slave will have problems trying to [...]
Concurrent inserts on MyISAM and the binary log
May 14, 2008 By 7 Comments
Recently I had an interesting surprise with concurrent inserts into a MyISAM table. The inserts were not happening concurrently with SELECT statements; they were blocking and the process list was filling up with queries in Locked status. My first thought was that the customer had deleted from the table, which leaves “holes” in the middle [...]
MySQL Replication vs DRBD Battles
April 28, 2008 By 12 Comments
Well these days we see a lot of post for and against (more, more) using of MySQL and DRBD as a high availability practice. I personally think DRBD has its place but there are far more cases when other techniques would work much better for variety of reasons. First let me start with Florian’s comments [...]
Innodb crash recovery update
May 22, 2007 By 3 Comments
I have not had a serious Innodb corruptions for a while, typically even if it happened it was some simple table related corruption which was easy to fix on table level. In couple of cases during last year when it was more than that we had backups and binary logs which means it was easier [...]
How to estimate time it takes Innodb to Recover ?
May 9, 2007 By 7 Comments
Today seems to be Innodb day in our Blog, but well this is the question which pops ups quite frequently in Innodb talks and during consulting engagements. It is well known to get better performance you should normally set innodb_log_file_size large. We however usually recommend caution as it may significantly increase recovery time if Innodb [...]
Using LVM for MySQL Backup and Replication Setup
August 21, 2006 By 53 Comments
If someone asks me about MySQL Backup advice my first question would be if they have LVM installed or have some systems with similar features set for other operation systems. Veritas File System can do it for Solaris. Most SAN systems would work as well. What is really needed is ability to create atomic snapshot [...]
