Linux: Use the byte order functions from <asm/byteorder.h>

[fio.git] / HOWTO.rst

diff --git a/HOWTO.rst b/HOWTO.rst
index b2750b566cf796115ad5022f90f06f3e02bd79c6..08be687c903db776baa7e75adcab6dc841febca2 100644 (file)
--- a/HOWTO.rst
+++ b/HOWTO.rst
@@ -1301,7 +1301,7 @@ I/O type
        effectively caps the file size at `real_size - offset`. Can be combined with
        :option:`size` to constrain the start and end range of the I/O workload.
        A percentage can be specified by a number between 1 and 100 followed by '%',
-       for example, ``offset=20%`` to specify 20%. In ZBD mode, value can be set as 
+       for example, ``offset=20%`` to specify 20%. In ZBD mode, value can be set as
         number of zones using 'z'.
 
 .. option:: offset_align=int
@@ -1877,7 +1877,7 @@ I/O size
        If this option is not specified, fio will use the full size of the given
        files or devices.  If the files do not exist, size must be given. It is also
        possible to give size as a percentage between 1 and 100. If ``size=20%`` is
-       given, fio will use 20% of the full size of the given files or devices. 
+       given, fio will use 20% of the full size of the given files or devices.
        In ZBD mode, value can also be set as number of zones using 'z'.
        Can be combined with :option:`offset` to constrain the start and end range
        that I/O will be done within.
@@ -3927,6 +3927,13 @@ Error handling
        appended, the total error count and the first error. The error field given
        in the stats is the first error that was hit during the run.
 
+       Note: a write error from the device may go unnoticed by fio when using
+       buffered IO, as the write() (or similar) system call merely dirties the
+       kernel pages, unless :option:`sync` or :option:`direct` is used. Device IO
+       errors occur when the dirty data is actually written out to disk. If fully
+       sync writes aren't desirable, :option:`fsync` or :option:`fdatasync` can be
+       used as well. This is specific to writes, as reads are always synchronous.
+
        The allowed values are:
 
                **none**