Add string support for buffer_pattern

[fio.git] / fio.1

diff --git a/fio.1 b/fio.1
index 22d6b1e882d10b2a543fb88ddf657387b3b35d94..e3334bd2b4de0a6b8850d669bce8932a48409982 100644 (file)
--- a/fio.1
+++ b/fio.1
@@ -478,7 +478,8 @@ size, fio can alternate random and zeroed data throughout the IO buffer.
 If set, fio will fill the IO buffers with this pattern. If not set, the contents
 of IO buffers is defined by the other options related to buffer contents. The
 setting can be any pattern of bytes, and can be prefixed with 0x for hex
-values.
+values. It may also be a string, where the string must then be wrapped with
+"".
 .TP
 .BI nrfiles \fR=\fPint
 Number of files to use for this job.  Default: 1.
@@ -612,6 +613,17 @@ options.
 Using Glusterfs libgfapi async interface to direct access to Glusterfs volumes without
 having to go through FUSE. This ioengine defines engine specific
 options.
+.TP
+.B libhdfs
+Read and write through Hadoop (HDFS).  The \fBfilename\fR option is used to
+specify host,port of the hdfs name-node to connect. This engine interprets
+offsets a little differently. In HDFS, files once created cannot be modified.
+So random writes are not possible. To imitate this, libhdfs engine expects
+bunch of small files to be created over HDFS, and engine will randomly pick a
+file out of those files based on the offset generated by fio backend. (see the
+example job file to create such files, use rw=write option). Please note, you
+might want to set necessary environment variables to work with hdfs/libhdfs
+properly.
 .RE
 .P
 .RE
@@ -657,10 +669,11 @@ Offset in the file to start I/O. Data before the offset will not be touched.
 .TP
 .BI offset_increment \fR=\fPint
 If this is provided, then the real offset becomes the
-offset + offset_increment * thread_number, where the thread number is a counter
-that starts at 0 and is incremented for each job. This option is useful if
-there are several jobs which are intended to operate on a file in parallel in
-disjoint segments, with even spacing between the starting points.
+offset + offset_increment * thread_number, where the thread number is a
+counter that starts at 0 and is incremented for each sub-job (i.e. when
+numjobs option is specified). This option is useful if there are several jobs
+which are intended to operate on a file in parallel disjoint segments, with
+even spacing between the starting points.
 .TP
 .BI number_ios \fR=\fPint
 Fio will normally perform IOs until it has exhausted the size of the region