… from the fact how MySQL‘s Transactions work with DDL, In particular ALTER TABLE. When ALTER TABLE is Performed in many cases… | +——————–+ | A | | B | | C | +——————–+ 3 rows in set (0.00 sec) mysql> select count(*) from A; +———-+ | count(*) | +———-+ | 2359296 | +———-+ 1 row in set… the duration of operation. You can also use Percona Xtrabackup, LVM or other database backup approach which does not relay on…
Post: Disaster: LVM Performance in Snapshot Mode
February 5, 2009 By 55 Comments
… test as our concern is general IO performance in this case – it is not something MySQL related. I tested things on RHEL5… performance without LVM snapshot was 159 io/sec which is quite expected for single thread and no BBU. With LVM snapshot enabled the performance… (in particular sequential file reads). If you’ve done some LVM performance tests yourself or will be repeating mine (parameters posted) please…
Post: How to Monitor MySQL with Percona's Nagios Plugins
February 22, 2012 By 8 Comments
… for our customers: Failed or full LVM snapshots. LVM backup strategies can fail to delete snapshots after…a system reboot. The pmp-check-mysql-pidfile plugin verifies that MySQL‘s PID file exists. Evidence …list, there are several others that can be performed with existing plugins, so there was no …
Post: LVM Configuration mistake to Avoid
July 9, 2008 By 10 Comments
One of our customers was setting up box for MySQL LVM backups. The box had 2 RAID volumes (internal drives and … volumes were configured as different “volume groups”. Volume groups in LVM live completely isolated life and you can’t use space….S That would be interested to benchmark one day how LVM performs in shapshot mode in case undo space is stored on…
Post: MySQL performance on EC2/EBS versus RDS
August 4, 2011 By 10 Comments
… overview of these two approaches to hosting MySQL in the Amazon cloud. In general, MySQL performance overall on EC2 and EBS isn’t… contention. The performance improvements I got with Percona Server were similar to the performance improvements I saw versus stock MySQL 5.1. This…. They work much better than LVM snapshots, in terms of impact to the system’s performance and ability to mount them on…
Post: Reasons for MySQL Replication Lag
July 29, 2011 By 6 Comments
… write-through mode which can cause serve performance degradation. Configuration Changes Have you changed MySQL configuration ? OS Configuration or Hardware configuration or… good” change as increasing buffer pool size could cause performance problems. MySQL Restart MySQL Restarts may include recovery time but what is the… forms. It can be you running backup through xtrabackup or LVM snapshot, RAID controller doing RAID validation, some centrally kicked of…
Post: Aligning IO on a hard disk RAID – the Benchmarks
June 9, 2011 By 11 Comments
… inode64 option however, the effect disappeared and performance without LVM was slightly better than with LVM as expected. I had to redo all… goal was to compare performance with different IO alignment, not different MySQL configurations, I didn’t try out different MySQL versions or settings…
Post: Estimating Undo Space needed for LVM Snapshot
June 9, 2008 By 5 Comments
… it is quite typical LVM is not configurable properly to be usable for MySQL Backups. Quite frequently I find LVM installed on the… etc are also possible trouble makers. Third,Use dedicated LVM volume for MySQL Instance. This is good idea for many reason and… should consider performance overheads mentioned in such operation. Actually exactly this configuration could be lifesaver if you have system with LVM setup…
Post: Using LVM for MySQL Backup and Replication Setup
August 21, 2006 By 53 Comments
… snapshot of many volumes. Lets speak a bit about how LVM and snapshotting in general works. Really there are different implementations… read-write snapshot is you can actually start MySQL Server on it and perform recovery, check tables or do whatever else you… need to do to perform backup of MySQL Database (or create slave) using LVM2 on Linux. 1) Connect to MySQL and run FLUSH…
Post: No more MySQL Crash Safe Replication in 5.0 ?
January 29, 2008 By 7 Comments
… functionality was usable is cloning Slave->Slave by use of LVM without pausing replication (so you can get consistent master position… more in MySQL 5.0 Baron has spotted it by incident when we were verifying some of examples for High Performance MySQL book. In the bug Heikki explains the code was probably removed in MySQL 5.0 during XA…
