As some of you likely know, I have a favorable view of ZFS and especially of MySQL on ZFS. As I published a few years ago, the argument for ZFS was less about performance than its useful features like data compression and snapshots. At the time, ZFS was significantly slower than xfs and ext4 except when the L2ARC was used.

Since then, however, ZFS on Linux has progressed a lot and I also learned how to better tune it. Also, I found out the sysbench benchmark I used at the time was not a fair choice since the dataset it generates compresses much less than a realistic one. For all these reasons, I believe that it is time to revisit the performance aspect of MySQL on ZFS.

ZFS Evolution

In 2018, I reported ZFS performance results based on version 0.6.5.6, the default version available in Ubuntu Xenial. The present post is using …

The short version

I created > one billion InnoDB tables in MySQL 8.0 (tables, not rows) just for fun. Here is the proof:

$ mysql -A
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 1425329
Server version: 8.0.12 MySQL Community Server - GPL
Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
mysql> select count(*) from information_schema.tables;
+------------+
| count(*)   |
+------------+
| 1011570298 |
+------------+
1 row in set (6 hours 57 min 6.31 sec)

Yes, it took 6 hours and 57 minutes to count them all!

Why does anyone need one billion tables?

In my previous blog post, I created and tested  …

In my previous blog post about millions of table in MySQL 8, I was able to create one million tables and test the performance of it. My next challenge is to create 40 million tables in MySQL 8 using shared tablespaces (one tablespace per schema). In this blog post I’m showing how to do it and what challenges we can expect.

Background

Once again – why do we need so many tables in MySQL, what is the use case? The main reason is: customer isolation. With the new focus on security and privacy (take GDPR for example) it is much easier and more beneficial to create a separate schema (or “database” in MySQL terms) for each customer. That creates a new set of challenges that we will need to solve. Here is the summary:

…

If you are a regular reader of this blog, you likely know I like the ZFS filesystem a lot. ZFS has many very interesting features, but I am a bit tired of hearing negative statements on ZFS performance. It feels a bit like people are telling me “Why do you use InnoDB? I have read that MyISAM is faster.” I found the comparison of InnoDB vs. MyISAM quite interesting, and I’ll use it in this post.

To have some data to support my post, I started an AWS i3.large instance with a 1000GB gp2 EBS volume. A gp2 volume of this size is interesting because it is above the burst IOPS level, so it offers a constant 3000 IOPS performance level.

I used sysbench to create a table of 10M rows and then, using export/import tablespace, I copied it 329 times. I ended up with 330 tables for a total size of about 850GB. The dataset generated by sysbench is not very compressible, so I used lz4 compression in ZFS. …

Please join Percona’s Principal Architect in Architecture & Projects, Yves Trudeau, as he presents ZFS with MySQL on Wednesday, March 28, 2018, at 7:00 am PDT (UTC -7) / 10:00 am EDT (UTC -4).

Are you curious about ZFS? Would you like to learn how to setup and configure ZFS? What about ZFS with MySQL?

ZFS on Linux has matured a lot. It offers unique features that are extremely compelling for use with a database server like MySQL.

During this webinar, we’ll review the main characteristics of ZFS, and walk through the configuration of ZFS and MySQL in order to provide good performance levels and superior ease-of-management. We will also cover aspects like backups using snapshots, cloning snapshots to create local slaves, the …

In this blog post, we’ll look at how ZFS affects MySQL performance when used in conjunction.

ZFS and MySQL have a lot in common since they are both transactional software. Both have properties that, by default, favors consistency over performance. By doubling the complexity layers for getting committed data from the application to a persistent disk, we are logically doubling the amount of work within the whole system and reducing the output. From the ZFS layer, where is really the bulk of the work coming from?

Consider a comparative test below from a bare metal server. It has a reasonably tuned config (discussed in separate post, results and scripts here). These numbers are from sysbench tests on hardware with six SAS drives behind a RAID controller with a write-backed cache. Ext4 was configured with RAID10 softraid, while ZFS …

This post is a hands-on look at ZFS with MySQL.

In my previous post, I highlighted the similarities between MySQL and ZFS. Before going any further, I’d like you to be able to play and experiment with ZFS. This post shows you how to configure ZFS with MySQL in a minimalistic way on either Ubuntu 16.04 or Centos 7.

Installation

In order to be able to use ZFS, you need some available storage space. For storage – since the goal here is just to have a hands-on experience – we’ll use a simple file as a storage device. Although simplistic, I have now been using a similar setup on my laptop for nearly three years (just can’t get rid of it, it is too useful). For simplicity, I suggest you use a small Centos7 or Ubuntu 16.04 VM with one core, 8GB of disk and 1GB of RAM.

First, you need to install …

While at Percona Live this year I was reminded about ZFS and running MySQL on top of a ZFS-based storage platform.

Now I’m a big fan of ZFS (although sadly I don’t get to use it as much as I used to after I shutdown my home server farm), and I did a lot of different testing back while at MySQL to ensure that MySQL, InnoDB and ZFS worked correctly together.

Of course today we have a completely new range of ZFS compatible environments, not least of which are FreeBSD and ZFS on Linux, I think it’s time to revisit some of my original advice on using this combination.

Unfortunately the presentations and MySQL University sessions back then have all been taken down. But that doesn’t mean the advice is any less valid.

Some of the core advice for using InnoDB on ZFS:

• Configure a single InnoDB tablespace, rather than configuring multiple tablespaces …

For the same customer I am exploring ZFS for backups, the twin server is using regular LVM and XFS. On this twin, I have setup mylvmbackup for a more conservative backup approach. I quickly found some odd behaviors, the backup was taking much longer than what I was expecting. It is not the first time I saw that, but here it was obvious. So I recorded some metrics, bi from vmstat and percent of cow space used from lvs during a backup. Cow space is the Copy On Write buffer used by LVM to record the modified pages like they were at the beginning of the snapshot. Upon reads, LVM must scan the list to verify that there’s no newer version. Here’s the other details about the backup:

• Filesystem: 2TB, xfs
• Snapsize: 60GB
• Amount to backup: ~600GB
• Backup tool: mylvmbackup
• Compressor: pbzip2

…

I am currently working with a large customer and I am involved with servers located in two data centers, one with Solaris servers and the other one with Linux servers. The Solaris side is cleverly setup using zones and ZFS and this provides a very low virtualization overhead. I learned quite a lot about these technologies while looking at this, thanks to Corey Mosher.

On the Linux side, we recently deployed a pair on servers for backup purpose, boxes with 64 300GB SAS drives, 3 raid controllers and 192GB of RAM. These servers will run a few slave instances each of production database servers and will perform the backups.  The write load is not excessive so a single server can easily handle the write load of all the MySQL instances.  The original idea was to configure them with raid-10 + LVM, making sure to …