Merge branch 'master' of ssh://git.kernel.dk/data/git/fio

[fio.git] / fio.1

diff --git a/fio.1 b/fio.1
index 81bcf061d4768808559d65f77ce60b62d969fc9b..e5451b1696f7a6b16754bf576a3531a8f81fd321 100644 (file)
--- a/fio.1
+++ b/fio.1
@@ -93,7 +93,7 @@ Start a backend server, with \fIargs\fP specifying what to listen to. See client
 Background a fio server, writing the pid to the given pid file.
 .TP
 .BI \-\-client \fR=\fPhost
-Instead of running the jobs locally, send and run them on the given host.
+Instead of running the jobs locally, send and run them on the given host or set of hosts.  See client/server section.
 .TP
 .BI \-\-idle\-prof \fR=\fPoption
 Report cpu idleness on a system or percpu basis (\fIoption\fP=system,percpu) or run unit work calibration only (\fIoption\fP=calibrate).
@@ -694,6 +694,17 @@ cost of more retrieval system calls.
 Low watermark indicating when to start filling the queue again.  Default:
 \fBiodepth\fR. 
 .TP
+.BI io_submit_mode \fR=\fPstr
+This option controls how fio submits the IO to the IO engine. The default is
+\fBinline\fR, which means that the fio job threads submit and reap IO directly.
+If set to \fBoffload\fR, the job threads will offload IO submission to a
+dedicated pool of IO threads. This requires some coordination and thus has a
+bit of extra overhead, especially for lower queue depth IO where it can
+increase latencies. The benefit is that fio can manage submission rates
+independently of the device completion rates. This avoids skewed latency
+reporting if IO gets back up on the device side (the coordinated omission
+problem).
+.TP
 .BI direct \fR=\fPbool
 If true, use non-buffered I/O (usually O_DIRECT).  Default: false.
 .TP
@@ -1254,6 +1265,12 @@ is to replay the IOPS onto the major/minor device that each IOP was recorded
 from.  Setting \fBreplay_redirect\fR causes all IOPS to be replayed onto the
 single specified device regardless of the device it was recorded from.
 .TP
+.BI replay_align \fR=\fPint
+Force alignment of IO offsets and lengths in a trace to this power of 2 value.
+.TP
+.BI replay_scale \fR=\fPint
+Scale sector offsets down by this factor when replaying traces.
+.TP
 .BI write_bw_log \fR=\fPstr
 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
@@ -1894,8 +1911,35 @@ to load a local file as well. This is done by using \-\-remote-config:
 
 fio \-\-client=server \-\-remote-config /path/to/file.fio
 
-Then the fio serer will open this local (to the server) job file instead
+Then fio will open this local (to the server) job file instead
 of being passed one from the client.
+
+If you have many servers (example: 100 VMs/containers), you can input a pathname 
+of a file containing host IPs/names as the parameter value for the \-\-client option.
+For example, here is an example "host.list" file containing 2 hostnames:
+
+host1.your.dns.domain
+.br
+host2.your.dns.domain
+
+The fio command would then be:
+
+fio \-\-client=host.list <job file>
+
+In this mode, you cannot input server-specific parameters or job files, and all
+servers receive the same job file.
+
+In order to enable fio \-\-client runs utilizing a shared filesystem from multiple hosts,
+fio \-\-client now prepends the IP address of the server to the filename. For example, 
+if fio is using directory /mnt/nfs/fio and is writing filename fileio.tmp, 
+with a \-\-client hostfile
+containing two hostnames h1 and h2 with IP addresses 192.168.10.120 and 192.168.10.121, then
+fio will create two files:
+
+/mnt/nfs/fio/192.168.10.120.fileio.tmp
+.br
+/mnt/nfs/fio/192.168.10.121.fileio.tmp
+
 .SH AUTHORS
 
 .B fio