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rbd: regenerate rbd(8) man page
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merge-diff and status commands, --image-features and --image-shared
options, other stuff.

Signed-off-by: Ilya Dryomov <[email protected]>
(cherry picked from commit 356a749)
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idryomov authored and jdurgin committed Mar 12, 2015
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61 changes: 44 additions & 17 deletions man/rbd.8
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@@ -1,6 +1,6 @@
.\" Man page generated from reStructuredText.
.
.TH "RBD" "8" "January 12, 2014" "dev" "Ceph"
.TH "RBD" "8" "March 12, 2015" "dev" "Ceph"
.SH NAME
rbd \- manage rados block device (RBD) images
.
Expand Down Expand Up @@ -187,6 +187,25 @@ See map options section below for more details.
.B \-\-read\-only
Map the image read\-only. Equivalent to \-o ro.
.UNINDENT
.INDENT 0.0
.TP
.B \-\-image\-features features
Specifies which RBD format 2 features are to be enabled when creating
an image. The numbers from the desired features below should be added
to compute the parameter value:
.sp
+1: layering support
+2: striping v2 support
+4: exclusive locking support
+8: object map support
.UNINDENT
.INDENT 0.0
.TP
.B \-\-image\-shared
Specifies that the image will be used concurrently by multiple clients.
This will disable features that are dependent upon exclusive ownership
of the image.
.UNINDENT
.SH COMMANDS
.INDENT 0.0
.TP
Expand All @@ -207,7 +226,8 @@ Will create a new rbd image. You must also specify the size via \-\-size. The
.B \fBclone\fP [\fIparent\-snapname\fP] [\fIimage\-name\fP]
Will create a clone (copy\-on\-write child) of the parent snapshot.
Object order will be identical to that of the parent image unless
specified. Size will be the same as the parent snapshot.
specified. Size will be the same as the parent snapshot. The \-\-stripe\-unit
and \-\-stripe\-count arguments are optional, but must be used together.
.sp
The parent snapshot must be protected (see \fIrbd snap protect\fP).
This requires image format 2.
Expand Down Expand Up @@ -242,6 +262,9 @@ Creates a new image and imports its data from path (use \- for
stdin). The import operation will try to create sparse rbd images
if possible. For import from stdin, the sparsification unit is
the data block size of the destination image (1 << order).
.sp
The \-\-stripe\-unit and \-\-stripe\-count arguments are optional, but must be
used together.
.TP
.B \fBexport\-diff\fP [\fIimage\-name\fP] [\fIdest\-path\fP] [\-\-from\-snap \fIsnapname\fP]
Exports an incremental diff for an image to dest path (use \- for stdout). If
Expand All @@ -251,6 +274,14 @@ using the standard \-\-snap option or @snap syntax (see below). The image diff
metadata about image size changes, and the start and end snapshots. It efficiently represents
discarded or \(aqzero\(aq regions of the image.
.TP
.B \fBmerge\-diff\fP [\fIfirst\-diff\-path\fP] [\fIsecond\-diff\-path\fP] [\fImerged\-diff\-path\fP]
Merge two continuous incremental diffs of an image into one single diff. The
first diff\(aqs end snapshot must be equal with the second diff\(aqs start snapshot.
The first diff could be \- for stdin, and merged diff could be \- for stdout, which
enables multiple diff files to be merged using something like
\(aqrbd merge\-diff first second \- | rbd merge\-diff \- third result\(aq. Note this command
currently only support the source incremental diff with stripe_count == 1
.TP
.B \fBimport\-diff\fP [\fIsrc\-path\fP] [\fIimage\-name\fP]
Imports an incremental diff of an image and applies it to the current image. If the diff
was generated relative to a start snapshot, we verify that snapshot already exists before
Expand Down Expand Up @@ -311,6 +342,9 @@ Unmaps the block device that was mapped via the rbd kernel module.
.B \fBshowmapped\fP
Show the rbd images that are mapped via the rbd kernel module.
.TP
.B \fBstatus\fP [\fIimage\-name\fP]
Show the status of the image, including which clients have it open.
.TP
.B \fBlock\fP list [\fIimage\-name\fP]
Show locks held on the image. The first column is the locker
to use with the \fIlock remove\fP command.
Expand Down Expand Up @@ -361,28 +395,21 @@ The striping is controlled by three parameters:
.INDENT 0.0
.TP
.B order
.TP
.B The size of objects we stripe over is a power of two, specifially 2^[*order*] bytes. The default
.TP
.B is 22, or 4 MB.
The size of objects we stripe over is a power of two, specifically 2^[\fIorder\fP] bytes. The default
is 22, or 4 MB.
.UNINDENT
.INDENT 0.0
.TP
.B stripe_unit
.TP
.B Each [*stripe_unit*] contiguous bytes are stored adjacently in the same object, before we move on
.TP
.B to the next object.
Each [\fIstripe_unit\fP] contiguous bytes are stored adjacently in the same object, before we move on
to the next object.
.UNINDENT
.INDENT 0.0
.TP
.B stripe_count
.TP
.B After we write [*stripe_unit*] bytes to [*stripe_count*] objects, we loop back to the initial object
.TP
.B and write another stripe, until the object reaches its maximum size (as specified by [*order*]. At that
.TP
.B point, we move on to the next [*stripe_count*] objects.
After we write [\fIstripe_unit\fP] bytes to [\fIstripe_count\fP] objects, we loop back to the initial object
and write another stripe, until the object reaches its maximum size (as specified by [\fIorder\fP]. At that
point, we move on to the next [\fIstripe_count\fP] objects.
.UNINDENT
.sp
By default, [\fIstripe_unit\fP] is the same as the object size and [\fIstripe_count\fP] is 1. Specifying a different
Expand Down Expand Up @@ -604,7 +631,7 @@ rbd lock remove mypool/myimage mylockid client.2485
.UNINDENT
.SH AVAILABILITY
.sp
\fBrbd\fP is part of Ceph, a massively scalable, open-source, distributed storage system. Please refer to
\fBrbd\fP is part of Ceph, a massively scalable, open\-source, distributed storage system. Please refer to
the Ceph documentation at \fI\%http://ceph.com/docs\fP for more information.
.SH SEE ALSO
.sp
Expand Down

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