X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=HOWTO;h=aaa46f801bd22d5ba113dc8726bafaf41d13858c;hb=ac002339c382d56ffcbf2b15a55d07d9d8c2eac6;hp=87346ae5acee4cdf62497adbbc556a9f88289c8c;hpb=b861be9f3eeb304fed875e327b175d110311873c;p=fio.git

diff --git a/HOWTO b/HOWTO
index 87346ae5..aaa46f80 100644
--- a/HOWTO
+++ b/HOWTO
@@ -159,6 +159,41 @@ specify:
 
 $ fio --name=random-writers --ioengine=libaio --iodepth=4 --rw=randwrite --bs=32k --direct=0 --size=64m --numjobs=4
 
+When fio is utilized as a basis of any reasonably large test suite, it might be
+desirable to share a set of standardized settings across multiple job files.
+Instead of copy/pasting such settings, any section may pull in an external
+.fio file with 'include filename' directive, as in the following example:
+
+; -- start job file including.fio --
+[global]
+filename=/tmp/test
+filesize=1m
+include glob-include.fio
+
+[test]
+rw=randread
+bs=4k
+time_based=1
+runtime=10
+include test-include.fio
+; -- end job file including.fio --
+
+; -- start job file glob-include.fio --
+thread=1
+group_reporting=1
+; -- end job file glob-include.fio --
+
+; -- start job file test-include.fio --
+ioengine=libaio
+iodepth=4
+; -- end job file test-include.fio --
+
+Settings pulled into a section apply to that section only (except global
+section). Include directives may be nested in that any included file may
+contain further include directive(s). Include files may not contain []
+sections.
+
+
 4.1 Environment variables
 -------------------------
 
@@ -565,10 +600,20 @@ buffer_compress_chunk=int	See buffer_compress_percentage. This
 		alternate random and zeroed data throughout the IO
 		buffer.
 
-buffer_pattern=str	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.
+buffer_pattern=str	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. It may also be a string, where the string must then
+		be wrapped with "".
+
+dedupe_percentage=int	If set, fio will generate this percentage of
+		identical buffers when writing. These buffers will be
+		naturally dedupable. The contents of the buffers depend on
+		what other buffer compression settings have been set. It's
+		possible to have the individual buffers either fully
+		compressible, or not at all. This option only controls the
+		distribution of unique buffers.
 
 nrfiles=int	Number of files to use for this job. Defaults to 1.
 
@@ -694,6 +739,22 @@ ioengine=str	Defines how the job issues io to the file. The following
 				having to go through FUSE. This ioengine
 				defines engine specific options.
 
+			libhdfs	Read and write through Hadoop (HDFS).
+				The 'filename' 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.
+
 			external Prefix to specify loading an external
 				IO engine object file. Append the engine
 				filename, eg ioengine=external:/tmp/foo.o