April 24, 2014

Inexpensive SSDs for Database Workloads

The cost of SSDs has been dropping rapidly, and at the time of this writing, 2.5-drives have reached the 1TB capacity mark.  You can actually get inexpensive drives for as little as 60 cents per GB. Even inexpensive SSDs can perform tens of thousands of IOPs and come with 1.5M – 2M hous MTBF and […]

The Math of Automated Failover

There are number of people recently blogging about MySQL automated failover, based on production incident which GitHub disclosed. Here is my take on it. When we look at systems providing high availability we can identify 2 cases of system breaking down. First is when the system itself has a bug or limitations which does not […]

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 […]

Setting up XFS on Hardware RAID — the simple edition

There are about a gazillion FAQs and HOWTOs out there that talk about XFS configuration, RAID IO alignment, and mount point options.  I wanted to try to put some of that information together in a condensed and simplified format that will work for the majority of use cases.  This is not meant to cover every […]

Aligning IO on a hard disk RAID – the Benchmarks

In the first part of this article I have showed how I align IO, now I want to share results of the benchmark that I have been running to see how much benefit can we get from a proper IO alignment on a 4-disk RAID1+0 with 64k stripe element. I haven’t been running any benchmarks […]

Death match! EBS versus SSD price, performance, and QoS

Is it a good idea to deploy your database into the cloud? It depends. I have seen it work well many times, and cause trouble at other times. In this blog post I want to examine cloud-based I/O. I/O matters a lot when a) the database’s working set is bigger than the server’s memory, or […]

Battery Learning still problem many years after

The performance problems caused by battery auto learning go many years back. We wrote about it, other people from MySQL Community too. The situation did not get better, at least not with Dell RAID controllers, H700 and H800 have the same problem too. At the same time situation got worse as a lot more people […]

The perils of uniform hardware and RAID auto-learn cycles

Last night a customer had an emergency in selected machines on a large cluster of quite uniform database servers. Some of the servers were slowing down in a very puzzling way over a short time span (a couple of hours). Queries were taking multiple seconds to execute instead of being practically instantaneous. But nothing seemed […]

Should I buy a Fast SSD or more memory?

While a scale-out solution has traditionally been popular for MySQL, it’s interesting to see what room we now have to scale up – cheap memory, fast storage, better power efficiency.  There certainly are a lot of options now – I’ve been meeting about a customer/week using Fusion-IO cards.  One interesting choice I’ve seen people make […]

How many fsync / sec FusionIO can handle

I recently was asked how many fsync / sec ( and therefore durable transactions / sec) we can get on FusionIO card. It should be easy to test, let’s take sysbench fileio benchmark and run, the next command should make it:

So that’s 9229.35 req/sec, which is pretty impressive. For comparison the same […]