Removed direct=1 options

[julio-santiesteban]

These are not supported on some platforms

[apollolemonte]

Even if they are not supported, I think the direct option should be the default to measure real disk performance and not buffered IO.

[julio-santiesteban]

measure real disk performance and not buffered IO.

direct = 0 is not buffered IO. direct = 1 is buffered. And both are supported, we're only talking about our example here (which I changed to non buffered for the sake of the e2e tests).

[julio-santiesteban]

@apollolemonte @otto-von-bivouac One more note here: direct = false (0, non-buffered) is actually the default: https://fio.readthedocs.io/en/latest/fio_doc.html#cmdoption-arg-direct

[otto-von-bivouac]

measure real disk performance and not buffered IO.

direct = 0 is not buffered IO. direct = 1 is buffered. And both are supported, we're only talking about our example here (which I changed to non buffered for the sake of the e2e tests).

The documentation states otherwise:

direct=bool
If value is true, use non-buffered I/O. This is usually O_DIRECT. Note that OpenBSD and ZFS on Solaris don’t support direct I/O. On Windows the synchronous ioengines don’t support direct I/O. Default: false.

That is, if you set direct to false we are going to measure page cache performance.