X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;ds=sidebyside;f=fio.1;h=c61948bb52814a2a6bac248c5db0063406225a48;hb=e6590c12f4a8c3f6de2adc9e127b1d2a0585ffae;hp=da44e570167fb16010fed7f6a392b6f3dc241f9f;hpb=ae5888523480f094ce04375a45797e111273ab22;p=fio.git

diff --git a/fio.1 b/fio.1
index da44e570..c61948bb 100644
--- a/fio.1
+++ b/fio.1
@@ -182,8 +182,8 @@ set. On Windows, disk devices are accessed as \\.\PhysicalDrive0 for the first
 device, \\.\PhysicalDrive1 for the second etc. Note: Windows and FreeBSD
 prevent write access to areas of the disk containing in-use data
 (e.g. filesystems). If the wanted filename does need to include a colon, then
-escape that with a '\' character. For instance, if the filename is
-"/dev/dsk/foo@3,0:c", then you would use filename="/dev/dsk/foo@3,0\:c".
+escape that with a '\\' character. For instance, if the filename is
+"/dev/dsk/foo@3,0:c", then you would use filename="/dev/dsk/foo@3,0\\:c".
 .TP
 .BI filename_format \fR=\fPstr
 If sharing multiple files between jobs, it is usually necessary to have
@@ -612,6 +612,17 @@ 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 +668,11 @@ 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
@@ -1191,17 +1203,21 @@ If given, write a bandwidth log of the jobs in this job file. Can be used to
 store data of the bandwidth of the jobs in their lifetime. The included
 fio_generate_plots script uses gnuplot to turn these text files into nice
 graphs. See \fBwrite_lat_log\fR for behaviour of given filename. For this
-option, the postfix is _bw.log.
+option, the postfix is _bw.x.log, where x is the index of the job (1..N,
+where N is the number of jobs)
 .TP
 .BI write_lat_log \fR=\fPstr
 Same as \fBwrite_bw_log\fR, but writes I/O completion latencies.  If no
-filename is given with this option, the default filename of "jobname_type.log"
-is used. Even if the filename is given, fio will still append the type of log.
+filename is given with this option, the default filename of
+"jobname_type.x.log" is used, where x is the index of the job (1..N, where
+N is the number of jobs). Even if the filename is given, fio will still
+append the type of log.
 .TP
 .BI write_iops_log \fR=\fPstr
 Same as \fBwrite_bw_log\fR, but writes IOPS. If no filename is given with this
-option, the default filename of "jobname_type.log" is used. Even if the
-filename is given, fio will still append the type of log.
+option, the default filename of "jobname_type.x.log" is used, where x is the
+index of the job (1..N, where N is the number of jobs). Even if the filename
+is given, fio will still append the type of log.
 .TP
 .BI log_avg_msec \fR=\fPint
 By default, fio will log an entry in the iops, latency, or bw log for every
@@ -1214,6 +1230,23 @@ Defaults to 0.
 If this is set, the iolog options will include the byte offset for the IO
 entry as well as the other data values.
 .TP
+.BI log_compression \fR=\fPint
+If this is set, fio will compress the IO logs as it goes, to keep the memory
+footprint lower. When a log reaches the specified size, that chunk is removed
+and compressed in the background. Given that IO logs are fairly highly
+compressible, this yields a nice memory savings for longer runs. The downside
+is that the compression will consume some background CPU cycles, so it may
+impact the run. This, however, is also true if the logging ends up consuming
+most of the system memory. So pick your poison. The IO logs are saved
+normally at the end of a run, by decompressing the chunks and storing them
+in the specified log file. This feature depends on the availability of zlib.
+.TP
+.BI log_store_compressed \fR=\fPbool
+If set, and \fBlog\fR_compression is also set, fio will store the log files in
+a compressed format. They can be decompressed with fio, using the
+\fB\-\-inflate-log\fR command line parameter. The files will be stored with a
+\fB\.fz\fR suffix.
+.TP
 .BI disable_lat \fR=\fPbool
 Disable measurements of total latency numbers. Useful only for cutting
 back the number of calls to \fBgettimeofday\fR\|(2), as that does impact performance at