[Ocfs2-tools-devel] [PATCH] mkfs.ocfs2: manpage update
tao.ma
tao.ma at oracle.com
Thu Sep 6 11:37:11 PDT 2007
Yeah, it really explain what I implement in mkfs.
Thanks for your work on this since I am quite sure I can't explain this
clearly in English. ;)
sob.
Mark Fasheh wrote:
> Add documentation for the --fs-feature-level and --fs-features flags.
>
> The actual text is included here as it's nearly impossible to read from the
> diff:
>
> --fs-features=[no]sparse...
> Turn specific file system features on or off. A comma separated
> list of feature flags can be provided, and mkfs.ocfs2 will try
> to create the file system with those features set according to
> the list. To turn a feature on, include it in the list. To turn
> a feature off, prepend no to the name. Choices here will over-
> ride individual features set via the --fs-feature-level option.
> The following flags are supported:
>
> local Create the file system as a local mount, so that it
> can be mounted without a cluster stack. See the -M
> option for more information.
>
> backup-super
> Create backup super blocks for this volume.
>
> sparse Enable support for sparse files. With this, Ocfs2
> can avoid allocating (and zeroing) data to fill
> holes. Turn this feature on if you can, otherwise
> extends and some writes might be less performant.
>
> unwritten
> Enable unwritten extents support. With this turned
> on, an application can request that a range of clus-
> ters be pre-allocated within a file. Ocfs2 will mark
> those extents with a special flag so that expensive
> data zeroing doesn't have to be performed. Reads and
> writes to a pre-allocated region act as reads and
> writes to a hole, except a write will not fail due
> to lack of data allocation. This feature requires
> sparse file support to be turned on.
>
> --fs-feature-level=feature-level
> Choose from a set of pre-determined file-system features. This
> option is designed to allow users to conveniently choose a set
> of file system features which fits their needs. There is no
> downside to trying a set of features which your module might not
> support - if it won't mount the new file system simply reformat
> at a lower level. Feature levels can be fine-tuned via the
> --fs-features option. Currently, there are 3 types of feature
> levels:
>
> max-compat
> Chooses fewer features but ensures that the file
> system can be mounted from older versions of the
> Ocfs2 module.
>
> default
> The default feature set tries to strike a balance
> between providing new features and maintaining com-
> patibility with relatively recent versions of Ocfs2.
>
> max-features
> Choose the maximum amount of features available.
> This will typically provide the best performance
> from Ocfs2 at the expense of creating a file system
> that is only compatible with very recent versions of
> the Ocfs2 kernel module.
>
> Signed-off-by: Mark Fasheh <mark.fasheh at oracle.com>
> ---
> mkfs.ocfs2/mkfs.ocfs2.8.in | 46 +++++++++++++++++++++++++++++++++++++++++++-
> 1 files changed, 45 insertions(+), 1 deletions(-)
>
> diff --git a/mkfs.ocfs2/mkfs.ocfs2.8.in b/mkfs.ocfs2/mkfs.ocfs2.8.in
> index 93eb318..a31bd16 100644
> --- a/mkfs.ocfs2/mkfs.ocfs2.8.in
> +++ b/mkfs.ocfs2/mkfs.ocfs2.8.in
> @@ -2,7 +2,7 @@
> .SH "NAME"
> mkfs.ocfs2 \- Creates an \fIOCFS2\fR file system.
> .SH "SYNOPSIS"
> -\fBmkfs.ocfs2\fR [\fB\-b\fR \fIblock\-size\fR] [\fB\-C\fR \fIcluster\-size\fR] [\fB\-L\fR \fIvolume\-label\fR] [\fB\-M\fR \fImount-type\fR] [\fB\-N\fR \fInumber\-of\-nodes\fR] [\fB\-J\fR \fIjournal\-options\fR] [\fB\-T\fR \fIfilesystem\-type\fR] [\fB\-FqvV\fR] [\fB\-\-no\-backup\-super\fR] \fIdevice\fR [\fIblocks-count\fI]
> +\fBmkfs.ocfs2\fR [\fB\-b\fR \fIblock\-size\fR] [\fB\-C\fR \fIcluster\-size\fR] [\fB\-L\fR \fIvolume\-label\fR] [\fB\-M\fR \fImount-type\fR] [\fB\-N\fR \fInumber\-of\-nodes\fR] [\fB\-J\fR \fIjournal\-options\fR] [\fB\-\-fs\-features=\fR\fI[no]sparse...\fR] [\fB\-\-fs\-feature\-level=\fR\fIfeature\-level\fR] [\fB\-T\fR \fIfilesystem\-type\fR] [\fB\-FqvV\fR] [\fB\-\-no\-backup\-super\fR] \fIdevice\fR [\fIblocks-count\fI]
> .SH "DESCRIPTION"
> .PP
> \fBmkfs.ocfs2\fR is used to create an \fIOCFS2\fR file system on a \fIdevice\fR,
> @@ -84,6 +84,50 @@ at least 128K.
> .RE
>
> .TP
> +\fB\-\-fs\-features=\fR\fR\fI[no]sparse...\fR
> +Turn specific file system features on or off. A comma separated list of feature flags can be provided, and mkfs.ocfs2 will try to create the file system with those features set according to the list. To turn a feature on, include it in the list. To turn a feature off, prepend \fBno\fR to the name. Choices here will override individual features set via the \fB\-\-fs\-feature\-level\fR option.
> +The following flags are supported:
> +.RS 1.2i
> +.TP
> +\fBlocal\fR
> +Create the file system as a local mount, so that it can be mounted without a cluster stack. See the \fB-M\fR option for more information.
> +.RE
> +.RS 1.2i
> +.TP
> +\fBbackup-super\fR
> +Create backup super blocks for this volume.
> +.RE
> +.RS 1.2i
> +.TP
> +\fBsparse\fR
> +Enable support for sparse files. With this, Ocfs2 can avoid allocating (and zeroing) data to fill holes. Turn this feature on if you can, otherwise extends and some writes might be less performant.
> +.RE
> +.RS 1.2i
> +.TP
> +\fBunwritten\fR
> +Enable unwritten extents support. With this turned on, an application can request that a range of clusters be pre-allocated within a file. Ocfs2 will mark those extents with a special flag so that expensive data zeroing doesn't have to be performed. Reads and writes to a pre-allocated region act as reads and writes to a hole, except a write will not fail due to lack of data allocation. This feature requires \fBsparse\fR file support to be turned on.
> +.RE
> +
> +.TP
> +\fB\-\-fs\-feature\-level=\fR\fR\fIfeature\-level\fR
> +Choose from a set of pre-determined file-system features. This option is designed to allow users to conveniently choose a set of file system features which fits their needs. There is no downside to trying a set of features which your module might not support - if it won't mount the new file system simply reformat at a lower level. Feature levels can be fine-tuned via the \fB\-\-fs\-features\fR option. Currently, there are 3 types of feature levels:
> +.RS 1.2i
> +.TP
> +\fBmax-compat\fR
> +Chooses fewer features but ensures that the file system can be mounted from older versions of the Ocfs2 module.
> +.RE
> +.RS 1.2i
> +.TP
> +\fBdefault\fR
> +The default feature set tries to strike a balance between providing new features and maintaining compatibility with relatively recent versions of Ocfs2.
> +.RE
> +.RS 1.2i
> +.TP
> +\fBmax-features\fR
> +Choose the maximum amount of features available. This will typically provide the best performance from Ocfs2 at the expense of creating a file system that is only compatible with very recent versions of the Ocfs2 kernel module.
> +.RE
> +
> +.TP
> \fB\-\-no-backup-super\fR
> \fBmkfs.ocfs2\fR, by default, makes upto 6 backup copies of the superblock
> at offsets 1G, 4G, 16G, 64G, 256G and 1T depending on the size of the volume.
>
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