MySQL 8.0 Reference Manual Including MySQL NDB Cluster 8.0

8.12.1 Optimizing Disk I/O

This section describes ways to configure storage devices when you can devote more and faster storage hardware to the database server. For information about optimizing an InnoDB configuration to improve I/O performance, see Section 8.5.8, “Optimizing InnoDB Disk I/O”.

Using NFS with MySQL

Caution is advised when considering using NFS with MySQL. Potential issues, which vary by operating system and NFS version, include:

  • MySQL data and log files placed on NFS volumes becoming locked and unavailable for use. Locking issues may occur in cases where multiple instances of MySQL access the same data directory or where MySQL is shut down improperly, due to a power outage, for example. NFS version 4 addresses underlying locking issues with the introduction of advisory and lease-based locking. However, sharing a data directory among MySQL instances is not recommended.

  • Data inconsistencies introduced due to messages received out of order or lost network traffic. To avoid this issue, use TCP with hard and intr mount options.

  • Maximum file size limitations. NFS Version 2 clients can only access the lowest 2GB of a file (signed 32 bit offset). NFS Version 3 clients support larger files (up to 64 bit offsets). The maximum supported file size also depends on the local file system of the NFS server.

Using NFS within a professional SAN environment or other storage system tends to offer greater reliability than using NFS outside of such an environment. However, NFS within a SAN environment may be slower than directly attached or bus-attached non-rotational storage.

If you choose to use NFS, NFS Version 4 or later is recommended, as is testing your NFS setup thoroughly before deploying into a production environment.