April 18, 2014

Is there room for more MySQL IO Optimization?

I prefer to run MySQL with innodb_flush_method=O_DIRECT in most cases – it makes sure there is no overhead of double buffering and I can save the limited amount of file system cache I would normally have on database server for those things which need to be cached — system files, binary log, FRM files, MySQL […]

Benchmarks of Intel 320 SSD 600GB

I have a chance to test a system with Intel 320 SSD drives (NewRelic provided me with an access to the server), and compare performance with SAS hard drives.

Looking for RAID Controller without Battery Learning problems ?

A lot have been written about Battery Learning Cycle problems and its impact to MySQL Performance. Here are couple of links (1,2). It is good to see though there are some controllers coming out which solve this problem, namely Adaptec 5Z series controllers (Z stands for Zero Maintenance). This is not quite new technology they […]

Side load may massively impact your MySQL Performance

When we’re looking at benchmarks we typically run some stable workload and we run it in isolation – nothing else is happening on the system. This is not however how things happen in real world when we have significant variance in the load and many things can be happening concurrently. It is very typical to […]

Recovering Linux software RAID, RAID5 Array

Dealing with MySQL you might need to deal with RAID recovery every so often. Sometimes because of client lacking the proper backup or sometimes because recovering RAID might improve recovery, for example you might get point in time recovery while backup setup only takes you to the point where last binary log was backed up. […]

Reasons for MySQL Replication Lag

One common theme in the questions our MySQL Support customers ask is MySQL Replication Lag. The story is typically along the lines everything is same as before and for some unknown reason the slave is started to lag and not catching up any more. I always smile at “nothing has changed” claim as it usually […]

InnoDB Flushing: a lot of memory and slow disk

You may have seen in the last couple of weekly news posts that Baron mentioned we are working on a new adaptive flushing algorithm in InnoDB. In fact, we already have three such algorithms in Percona Server (reflex, estimate, keep_average). Why do we need one more? Okay, first let me start by showing the current […]

MySQL on Amazon RDS part 2: Determining Peak Throughput

This is a continuation of my series of benchmark posts comparing Amazon RDS to a server running on Amazon EC2. Upcoming posts (probably 6 or 8 in total) will extend the scope of the benchmark to include data on our Dell r900 with traditional hard drives in RAID10, and a server in the Joyent cloud. […]

Virtualization and IO Modes = Extra Complexity

It has taken a years to get a proper integration between operating system kernel, device driver and hardware to get behavior with caches and IO modes correctly. I remember us having a lot of troubles with fsync() not flushing hard drive write cache and so potential hard drives can be lost on power failure. Happily […]

Modeling MySQL Capacity by Measuring Resource Consumptions

There are many angles you can look at the system to predict in performance, the model baron has published for example is good for measuring scalability of the system as concurrency growths. In many cases however we’re facing a need to answer a question how much load a given system can handle when load is […]