XFS or EXT4 - MySQL Best Filesystem for Galera Cluster?

[Chris Young]

Greetings everyone,

First, thanks for all of your help, you have provided me with priceless knowledge and information about this product - I am very appreciative.  

I have a quick question, I've been doing a lot of searching on the net for what might be the filesystem of choice for Galera/MySQL InnoDB.

I have read pros and cons for both XFS and EXT4 filesystems so I thought I would find out from the true experts in this field.

We will be eventually deploying a Galera cluster on EC2 utilizing RedHat Linux.   The initial cluster will be 3 MySQL servers.  On the spectrum of heavy reads to heavy writes,  I would estimate that we would be somewhere in the middle of this.  

I know that both of these filesystem types (XFS and EXT4) are the preferred choices, but is there one that stands out better than the other that is particular to RedHat?  I'm just looking for some best practices recommendations and I just want to make sure that the correct FS is chosen initially to avoid the possibility of having to change things in the future.

Your input again is highly valued and appreciated, thank you again;

Chris

[Alex Yurchenko]

Hi,

I don't think that Galera has any particular preferences with respect
to a filesystem. Its own filesystem usage is rather lenient - it never
flushes (except once per DDL) and its access is very much sequential.
Under circumstances it may need to create large page files for cache. I
don't know which of XFS or EXT4 is best at it, but it hardly should be a
criterion of choice.

Rather the choice depends on your load profile, instance choice, use of
EBS, use of RAID, InnoDB settings and so on. Use recommendations for
regular MySQL. Galera is of least importance here.

Well, ok, maybe not of the least. Galera allows you to disable
innodb_flush_log_at_trx_commit. That can make a difference. But I doubt
anybody benchmarked that. So it is up to you.

Regards,
Alex

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[Henrik Ingo]

Hi Chris

Personally I have the impression MySQL performance experts prefer XFS.

Dmitry from Oracle MySQL performance team has several good blog posts
benchmarking filesystems:
http://dimitrik.free.fr/blog/index.html

henrik

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