First snapshot of FIO for Windows

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index d3639fb487d2c3fa206b1789ad59132e12e83e0c..3b1eeb0606832a7808b43c309673079b3303d11f 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -271,12 +271,14 @@ filename=str      Fio normally makes up a filename based on the job name,
                can specify a number of files by separating the names with a
                ':' colon. So if you wanted a job to open /dev/sda and /dev/sdb
                as the two working files, you would use
                can specify a number of files by separating the names with a
                ':' colon. So if you wanted a job to open /dev/sda and /dev/sdb
                as the two working files, you would use

-               filename=/dev/sda:/dev/sdb. 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". '-' is a reserved name,
-               meaning stdin or stdout. Which of the two depends on the read/write
-               direction set.
+               filename=/dev/sda:/dev/sdb. On Windows, disk devices are accessed
+               as /dev/sda for the first device (i.e. \Device\HardDisk0\Partition0,
+               /dev/sda1 for the first partition on the first disk etc.  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". 
+               '-' is a reserved name, meaning stdin or stdout. Which of the 
+               two depends on the read/write direction set.

 
 opendir=str    Tell fio to recursively add any file it can find in this
                directory and down the file system tree.
 
 opendir=str    Tell fio to recursively add any file it can find in this
                directory and down the file system tree.


@@ -492,6 +494,8 @@ ioengine=str        Defines how the job issues io to the file. The following
 
                        solarisaio Solaris native asynchronous io.
 
 
                        solarisaio Solaris native asynchronous io.
 

+                       windowsaio Windows native asynchronous io.
+

                        mmap    File is memory mapped and data copied
                                to/from using memcpy(3).
 
                        mmap    File is memory mapped and data copied
                                to/from using memcpy(3).
 


@@ -549,7 +553,14 @@ ioengine=str       Defines how the job issues io to the file. The following
 iodepth=int    This defines how many io units to keep in flight against
                the file. The default is 1 for each file defined in this
                job, can be overridden with a larger value for higher
 iodepth=int    This defines how many io units to keep in flight against
                the file. The default is 1 for each file defined in this
                job, can be overridden with a larger value for higher

-               concurrency.
+               concurrency. Note that increasing iodepth beyond 1 will not
+               affect synchronous ioengines (except for small degress when
+               verify_async is in use). Even async engines my impose OS
+               restrictions causing the desired depth not to be achieved.
+               This may happen on Linux when using libaio and not setting
+               direct=1, since buffered IO is not async on that OS. Keep an
+               eye on the IO depth distribution in the fio output to verify
+               that the achieved depth is as expected. Default: 1.

 
 iodepth_batch_submit=int
 iodepth_batch=int This defines how many pieces of IO to submit at once.
 
 iodepth_batch_submit=int
 iodepth_batch=int This defines how many pieces of IO to submit at once.


@@ -935,13 +946,18 @@ verify_backlog=int        Fio will normally verify the written contents of a
                associated with an IO block in memory, so for large
                verify workloads, quite a bit of memory would be used up
                holding this meta data. If this option is enabled, fio
                associated with an IO block in memory, so for large
                verify workloads, quite a bit of memory would be used up
                holding this meta data. If this option is enabled, fio

+               will write only N blocks before verifying these blocks.
+

                will verify the previously written blocks before continuing
                to write new ones.
 
 verify_backlog_batch=int       Control how many blocks fio will verify
                if verify_backlog is set. If not set, will default to
                the value of verify_backlog (meaning the entire queue
                will verify the previously written blocks before continuing
                to write new ones.
 
 verify_backlog_batch=int       Control how many blocks fio will verify
                if verify_backlog is set. If not set, will default to
                the value of verify_backlog (meaning the entire queue

-               is read back and verified).
+               is read back and verified).  If verify_backlog_batch is
+               less than verify_backlog then not all blocks will be verified,
+               if verify_backlog_batch is larger than verify_backlog, some
+               blocks will be verified more than once.

                
 stonewall      Wait for preceeding jobs in the job file to exit, before
                starting this one. Can be used to insert serialization
                
 stonewall      Wait for preceeding jobs in the job file to exit, before
                starting this one. Can be used to insert serialization


@@ -1287,4 +1303,4 @@ Split up, the format is as follows:
        IO latencies milliseconds: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, 2000, >=2000
        Additional Info (dependant on continue_on_error, default off): total # errors, first error code 
        
        IO latencies milliseconds: <=2, 4, 10, 20, 50, 100, 250, 500, 750, 1000, 2000, >=2000
        Additional Info (dependant on continue_on_error, default off): total # errors, first error code 
        

-       Additional Info (dependant on description being set): Text description
\ No newline at end of file
+       Additional Info (dependant on description being set): Text description