Now that flash storage is becoming more popular, IO alignment question keeps popping up more often than it used to when all we had were rotating hard disk drives. I think the reason is very simple – when systems only had one bearing hard disk drive (HDD) as in RAID1 or one disk drive at [...]
Spreading .ibd files across multiple disks; the optimization that isn’t
December 25, 2010 By 23 Comments
Inspired by Baron’s earlier post, here is one I hear quite frequently – “If you enable innodb_file_per_table, each table is it’s own .ibd file. You can then relocate the heavy hit tables to a different location and create symlinks to the original location.” There are a few things wrong with this advice:
The Doom of Multiple Storage Engines
May 8, 2010 By 22 Comments
One of the big “Selling Points” of MySQL is support for Multiple Storage engines, and from the glance view it is indeed great to provide users with same top level SQL interface allowing them to store their data many different way. As nice as it sounds the in theory this benefit comes at very significant [...]
State of the art: Galera – synchronous replication for InnoDB
October 27, 2009 By 15 Comments
First time I heard about Galera on Percona Performance Conference 2009, Seppo Jaakola was presenting “Galera: Multi-Master Synchronous MySQL Replication Clusters”. It was impressed as I personally always wanted it for InnoDB, but we had it in plans at the bottom of the list, as this is very hard to implement properly. The idea by [...]
EC2/EBS single and RAID volumes IO benchmark
August 6, 2009 By 14 Comments
During preparation of Percona-XtraDB template to run in RightScale environment, I noticed that IO performance on EBS volume in EC2 cloud is not quite perfect. So I have spent some time benchmarking volumes. Interesting part with EBS volumes is that you see it as device in your OS, so you can easily make software RAID [...]
Detailed review of Tokutek storage engine
April 28, 2009 By 21 Comments
(Note: Review was done as part of our consulting practice, but is totally independent and fully reflects our opinion) I had a chance to take look TokuDB (the name of the Tokutek storage engine), and run some benchmarks. Tuning of TokuDB is much easier than InnoDB, there only few parameters to change, and actually out-of-box [...]
Disaster: LVM Performance in Snapshot Mode
February 5, 2009 By 55 Comments
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 [...]
Troubleshooting Relay Log Corruption in MySQL
August 2, 2008 By 7 Comments
Have you ever seen the replication stopped with message like this: Last_Error: Could not parse relay log event entry. The possible reasons are: the master’s binary log is corrupted (you can check this by running ‘mysqlbinlog’ on the binary log), the slave’s relay log is corrupted (you can check this by running ‘mysqlbinlog’ on the [...]
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 [...]
