HOWTO/man: Describe trim support by zone reset for zoned devices

[fio.git] / fio.1

diff --git a/fio.1 b/fio.1
index 8d2d20b67e676079c0019d5e8c3445c4ef86bb45..ff100a1ca6725a08426043c85010d96fc94f1009 100644 (file)
--- a/fio.1
+++ b/fio.1
@@ -766,6 +766,8 @@ starts. The \fBzonecapacity\fR parameter is ignored.
 Zoned block device mode. I/O happens sequentially in each zone, even if random
 I/O has been selected. Random I/O happens across all zones instead of being
 restricted to a single zone.
+Trim is handled using a zone reset operation. Trim only considers non-empty
+sequential write required and sequential write preferred zones.
 .RE
 .RE
 .TP
@@ -1509,6 +1511,48 @@ all \-\- this option only controls the distribution of unique buffers. Setting
 this option will also enable \fBrefill_buffers\fR to prevent every buffer
 being identical.
 .TP
+.BI dedupe_mode \fR=\fPstr
+If \fBdedupe_percentage\fR is given, then this option controls how fio
+generates the dedupe buffers.
+.RS
+.RS
+.TP
+.B repeat
+.P
+.RS
+Generate dedupe buffers by repeating previous writes
+.RE
+.TP
+.B working_set
+.P
+.RS
+Generate dedupe buffers from working set
+.RE
+.RE
+.P
+\fBrepeat\fR is the default option for fio. Dedupe buffers are generated
+by repeating previous unique write.
+
+\fBworking_set\fR is a more realistic workload.
+With \fBworking_set\fR, \fBdedupe_working_set_percentage\fR should be provided.
+Given that, fio will use the initial unique write buffers as its working set.
+Upon deciding to dedupe, fio will randomly choose a buffer from the working set.
+Note that by using \fBworking_set\fR the dedupe percentage will converge
+to the desired over time while \fBrepeat\fR maintains the desired percentage
+throughout the job.
+.RE
+.RE
+.TP
+.BI dedupe_working_set_percentage \fR=\fPint
+If \fBdedupe_mode\fR is set to \fBworking_set\fR, then this controls
+the percentage of size of the file or device used as the buffers
+fio will choose to generate the dedupe buffers from
+.P
+.RS
+Note that \fBsize\fR needs to be explicitly provided and only 1 file
+per job is supported
+.RE
+.TP
 .BI invalidate \fR=\fPbool
 Invalidate the buffer/page cache parts of the files to be used prior to
 starting I/O if the platform and file type support it. Defaults to true.
@@ -1658,9 +1702,7 @@ Sets size to something really large and waits for ENOSPC (no space left on
 device) or EDQUOT (disk quota exceeded)
 as the terminating condition. Only makes sense with sequential
 write. For a read workload, the mount point will be filled first then I/O
-started on the result. This option doesn't make sense if operating on a raw
-device node, since the size of that is already known by the file system.
-Additionally, writing beyond end-of-device will not return ENOSPC there.
+started on the result.
 .SS "I/O engine"
 .TP
 .BI ioengine \fR=\fPstr
@@ -1721,10 +1763,9 @@ character devices. This engine supports trim operations. The
 sg engine includes engine specific options.
 .TP
 .B libzbc
-Synchronous I/O engine for SMR hard-disks using the \fBlibzbc\fR
-library. The target can be either an sg character device or
-a block device file. This engine supports the zonemode=zbd zone
-operations.
+Read, write, trim and ZBC/ZAC operations to a zoned block device using
+\fBlibzbc\fR library. The target can be either an SG character device or
+a block device file.
 .TP
 .B null
 Doesn't transfer any data, just pretends to. This is mainly used to