Deprecated mount option in Linux kernel 4.15+

[pjaclark]

The mount options barrier|nobarrier has been deprecated.

This affects:

• RHEL 8+
• Ubuntu 18.04+
• Any other OS using kernel 4.15 (which came out 2018-01-28)

Pages:

• https://www.tiot.jp/riak-docs/riak/kv/2.9.10/using/performance/#filesystem

Change:

Similarly, the XFS file system defaults can be optimized to improve performance. We recommend setting `nobarrier`, `logbufs=8`, `logbsize=256k`, and `allocsize=2M` when using the XFS filesystem.

To:

Similarly, the XFS file system defaults can be optimized to improve performance. We recommend setting `logbufs=8`, `logbsize=256k`, and `allocsize=2M` when using the XFS filesystem. In addition, up to Ubuntu 17.10 and RHEL/CentOS 7.9 (and any OS using a Linux kernel before 4.15) we recommend setting `nobarrier`.