Documentation update

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 6c7f05b9efde3334e5260b4c86371216d43de3b3..3e1e62a0f4d3115fa947471febf2796150eae9f2 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -823,7 +823,9 @@ verify=str  If writing to a file, fio can verify the file contents
                                it in the header of each block.
 
                        crc32c-intel Use hardware assisted crc32c calcuation
                                it in the header of each block.
 
                        crc32c-intel Use hardware assisted crc32c calcuation

-                               provided on SSE4.2 enabled processors.
+                               provided on SSE4.2 enabled processors. Falls
+                               back to regular software crc32c, if not
+                               supported by the system.

 
                        crc32   Use a crc32 sum of the data area and store
                                it in the header of each block.
 
                        crc32   Use a crc32 sum of the data area and store
                                it in the header of each block.


@@ -899,6 +901,22 @@ verify_async=int   Fio will normally verify IO inline from the submitting
 verify_async_cpus=str  Tell fio to set the given CPU affinity on the
                async IO verification threads. See cpus_allowed for the
                format used.
 verify_async_cpus=str  Tell fio to set the given CPU affinity on the
                async IO verification threads. See cpus_allowed for the
                format used.

+
+verify_backlog=int     Fio will normally verify the written contents of a
+               job that utilizes verify once that job has completed. In
+               other words, everything is written then everything is read
+               back and verified. You may want to verify continually
+               instead for a variety of reasons. Fio stores the meta data
+               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 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).

                
 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


@@ -942,7 +960,7 @@ read_iolog=str      Open an iolog with the specified file name and replay the
                to replay a workload captured by blktrace. See blktrace
                for how to capture such logging data. For blktrace replay,
                the file needs to be turned into a blkparse binary data
                to replay a workload captured by blktrace. See blktrace
                for how to capture such logging data. For blktrace replay,
                the file needs to be turned into a blkparse binary data

-               file first (blktrace <device> -d file_for_fio.bin).
+               file first (blkparse <device> -o /dev/null -d file_for_fio.bin).

 
 write_bw_log=str If given, write a bandwidth log of the jobs in this job
                file. Can be used to store data of the bandwidth of the
 
 write_bw_log=str If given, write a bandwidth log of the jobs in this job
                file. Can be used to store data of the bandwidth of the


@@ -1036,6 +1054,12 @@ cgroup_weight=int        Set the weight of the cgroup to this value. See
                the documentation that comes with the kernel, allowed values
                are in the range of 100..1000.
 
                the documentation that comes with the kernel, allowed values
                are in the range of 100..1000.
 

+cgroup_nodelete=bool Normally fio will delete the cgroups it has created after
+               the job completion. To override this behavior and to leave
+               cgroups around after the job completion, set cgroup_nodelete=1.
+               This can be useful if one wants to inspect various cgroup
+               files after job completion. Default: false
+

 uid=int                Instead of running as the invoking user, set the user ID to
                this value before the thread/process does any work.
 
 uid=int                Instead of running as the invoking user, set the user ID to
                this value before the thread/process does any work.