In many cases I speculate how things should work based on what they do and in number of cases this lead me forming too good impression about technology and when running in completely unanticipated bug or performance bottleneck. This is exactly the case with LVM Number of customers have reported the LVM gives very high [...]
How Percona does a MySQL Performance Audit
November 24, 2008 By 17 Comments
Our customers or prospective customers often ask us how we do a performance audit (it’s our most popular service). I thought I should write a blog post that will both answer their question, so I can just reply “read all about it at this URL” and share our methodology with readers a little bit. This [...]
Thoughs on Innodb Incremental Backups
November 10, 2008 By 8 Comments
For normal Innodb “hot” backups we use LVM or other snapshot based technologies with pretty good success. However having incremental backups remain the problem. First why do you need incremental backups at all ? Why not just take the full backups daily. The answer is space – if you want to keep several generations to [...]
Recovery beyond data restore
August 2, 2008 By 11 Comments
Quite frequently I see customers looking at recovery as on ability to restore data from backup which can be far from being enough to restore the whole system to operating state, especially for complex systems. Instead of looking just at data restore process you better look at the whole process which is required to bring [...]
How SHOW SLAVE STATUS relates to CHANGE MASTER TO
July 7, 2008 By 21 Comments
As you probably know MySQL Replication (statement based) works by fetching statements from MASTERs binary log and executing them on the SLAVE. Since MySQL 4.0 this process is a bit more involved having events passing via relay logs on the Slave which also means there are two replication threads “IO Thread” and “SQL Thread” used [...]
Estimating Undo Space needed for LVM Snapshot
June 9, 2008 By 5 Comments
We know MySQL Backups using LVM are pretty cool (check out mylvmbackup) or MMM though it is quite typical LVM is not configurable properly to be usable for MySQL Backups. Quite frequently I find LVM installed on the system but no free space left to be used as snapshot undo space, which means LVM is [...]
No more MySQL Crash Safe Replication in 5.0 ?
January 29, 2008 By 7 Comments
As you might know even if you’re only using Innodb tables your replication is not completely crash safe – if Slave MySQL Server crashes/power goes down it is likely for relay logs to run out of sync (they are not synced to the disk) plus position on the master which slave remembers becomes stale. During [...]
Performance impact of complex queries
January 17, 2007 By 11 Comments
What is often underestimated is impact of MySQL Performance by complex queries on large data sets(ie some large aggregate queries) and batch jobs. It is not rare to see queries which were taking milliseconds to stall for few seconds, especially in certain OS configurations, and on low profile servers (ie having only one disk drive) [...]
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 [...]
