'\" t
.\"     Title: drbdmeta
.\"    Author: [see the "Author" section]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 6 December 2012
.\"    Manual: System Administration
.\"    Source: DRBD 9.0.0
.\"  Language: English
.\"
.TH "DRBDMETA" "8" "6 December 2012" "DRBD 9.0.0" "System Administration"
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.SH "NAME"
drbdmeta \- Manipulate the DRBD on\-disk metadata
.SH "SYNOPSIS"
.HP \w'\fBdrbdmeta\fR\ 'u
\fBdrbdmeta\fR [\-\-force] [\-\-ignore\-sanity\-checks] {\fIdevice\fR} {v06\ \fIminor\fR | v07\ \fImeta_dev\ index\fR | v08\ \fImeta_dev\ index\fR | v09\ \fImeta_dev\ index\fR} {\fIcommand\fR} [\fIcmd\ args\fR...]
.SH "DESCRIPTION"
.PP
The
\fBdrbdmeta\fR
utility is used for creating, displaying, and modifying DRBD\*(Aqs on\-disk metadata\&. Users usually interact with the
\fBdrbdadm\fR
utility, which provides a more high\-level interface to DRBD than
\fBdrbdmeta\fR\&. (See
\fBdrbdadm\fR\*(Aqs
\fB\-\-dry\-run\fR
option to see how
\fBdrbdadm\fR
uses
\fBdrbdmeta\fR\&.)
.PP
This utility can only be used on devices which are not currently in use by the kernel\&.
.PP
The first argument (\fIdevice\fR) specifies the drbd device associated with a volume, or
\(lq\-\(rq
if no device is associated with that volume\&. If the drbd device is specified, the
\fBdrbdmeta\fR
utility makes sure that the drbd device does not currently have a volume attached to prevent meta\-data of an active volume from being destroyed\&.
.PP
The second argument specifies the metadata version to use (v06, v07, v08, v09)\&. In most metadata versions, the third argument (\fImeta_dev\fR) specifies the device which contains the metadata; this argument can be the same as
\fIdevice\fR\&. The fourth argument (\fIindex\fR) can be one of the keywords
\fBinternal\fR
(for internal metadata),
\fBflex\-internal\fR
(in v07 for variable\-sized metadata; v07 otherwise defaults to fixed\-size internal metadata),
\fBflex\-external\fR
(for variable\-sized external metadata), or a numeric matadata index (for fixed\-size external metadata)\&. See the
\fBmeta\-disk\fR
parameter in
\fBdrbd.conf\fR(5)\&.
.SH "OPTIONS"
.PP
\-\-force
.RS 4

Assume yes as the answer to all questions drbdmeta would ask\&.
.RE
.PP
\-\-ignore\-sanity\-checks
.RS 4

Normally,
\fBdrbdmeta\fR
performs some sanity checks before writing to the metadata device: for example, if the device appears to contain a file system, it refuses to destroy the file system by writing into it\&. Use this option to ignore these checks\&.
.RE
.SH "COMMANDS"
.PP
\fBcreate\-md\fR [\fB\-\-peer\-max\-bio\-size=\fR\fIval\fR] (metadata versions v06, v07, and v08), 
.br
\fBcreate\-md\fR {number\-of\-bitmap\-slots} [\fB\-\-peer\-max\-bio\-size=\fR\fIval\fR] [\fB\-\-initialize\-bitmap\-mode=\fR\fI{automatic|zeroout|pwrite|skip}\fR] [\fB\-\-al\-stripes=\fR\fIval\fR] [\fB\-\-al\-stripe\-size\-kB=\fR\fIval\fR] (metadata version v09)
.RS 4

Initialize the metadata\&. This is necessary before a DRBD resource can be attached\&. If
\fBdrbdmeta\fR
finds an older version of DRBD metadata on the device, it asks if the format should be converted\&.
.sp
When
\fBdrbdadm\fR
calls
\fBdrbdmeta\fR\*(Aqs
\fBcreate\-md\fR
command for a device, it sets the
\fInumber\-of\-bitmap\-slots\fR
argument to the number of peers in the resource\&. To reserve additional bitmap slots (which allows to add more peers in the future), call
\fBdrbdmeta\fR
directly instead\&.
.sp
When a device is used before being connected to its peers the first time, DRBD assumes that peers can only handle 4 KiB requests by default\&. The
\fB\-\-peer\-max\-bio\-size\fR
option allows to set more optimistic values; use this if the versions of DRBD that this device will connect to are known\&. DRBD supports a maximum bio size of 32 KiB since version 8\&.3\&.8, of 128 KiB since version 8\&.3\&.9, and of 1 MiB since version 8\&.4\&.0\&.
.sp
By default, we explicitly initialize the bitmap area to all zero\&. With
\fB\-\-initialize\-bitmap\-mode\fR
you can chose to only try the fast method (\fBzeroout\fR, try ioctl BLKZEROOUT only), only use explicit
\fBpwrite\fR
calls, or
\fBskip\fR
this bitmap initialization phase completely\&. If you intend to do an initial full sync anyways, you can use
\fBskip\fR
to leave the bitmap initialization to the kernel\&. This can make a noticable difference when initializing huge volumes\&. Default is
\fBautomatic\fR, which is zeroout with an implicit fallback to pwrite\&.
.sp
If you want to use more than 6433 activity log extents, or live on top of a spriped RAID, you may specify the number of stripes (\fB\-\-al\-stripes\fR, default 1), and the stripe size (\fB\-\-al\-stripe\-size\-kB\fR, default 32)\&. To just use a larger linear on\-disk ring\-buffer, leave the number of stripes at 1, and increase the size only:

\fBdrbdmeta 0 v08 /dev/vg23/lv42 internal create\-md \-\-al\-stripe\-size 1M\fR
.sp
To avoid a single "spindle" from becoming a bottleneck, increase the number of stripes, to achieve an interleaved layout of the on\-disk activity\-log transactions\&. What you give as "stripe\-size" should be what is a\&.k\&.a\&. "chunk size" or "granularity" or "strip unit": the minimum skip to the next "spindle"\&.

\fBdrbdmeta 0 v08 /dev/vg23/lv42 internal create\-md \-\-al\-stripes 7 \-\-al\-stripe\-size 64\fR
.RE
.PP
\fBget\-gi\fR [\fB\-\-node\-id=\fR\fIid\fR]
.RS 4

Show the data generation identifiers for a device on a particular connection\&. DRBD version 9\&.0\&.0 and beyond support multiple peers; use the
\fInode\-id\fR
option to define which peer\*(Aqs data generation identifiers to show\&.
.RE
.PP
\fBshow\-gi\fR [\fB\-\-node\-id=\fR\fIid\fR]
.RS 4

Similar to
\fBget\-gi\fR, but with explanatory information\&.
.RE
.PP
\fBdump\-md\fR
.RS 4

Dump the metadata of a device in text form, including the bitmap and activity log\&.
.RE
.PP
\fBoutdate\fR
.RS 4
Mark the data on a lower\-level device as outdated\&. See
\fBdrbdsetup\fR(8)
for details\&.
.RE
.PP
\fBdstate\fR
.RS 4
Show the current disk state of a lower\-level device\&.
.RE
.PP
\fBcheck\-resize\fR
.RS 4

Examine the device size of a lower\-level device and its last known device size (saved in
\fB/var/lib/drbd/drbd\-minor\-\fR\fB\fIminor\fR\fR\fB\&.lkbd\fR
by
\fBdrbdsetup check\-resize\fR)\&. For internal metadata, if the size of the lower\-level device has changed and the metadata can be found at the previous position, move the metadata to the new position at the end of the block device\&.
.RE
.PP
\fBapply\-al\fR
.RS 4

Apply the activity log of the specified device\&. This is necessary before the device can be attached by the kernel again\&.
.RE
.SH "EXPERT COMMANDS"
.PP
The
\fBdrbdmeta\fR
utility can be used to fine tune metdata\&. Please note that this can lead to destroyed metadata or even silent data corruption; use with great care only\&.
.PP
\fBset\-gi\fR \fIgi\fR [\fB\-\-node\-id=\fR\fIid\fR]
.RS 4

Set the generation identifiers\&. The
\fIgi\fR
argument is a generation counter for the v06 and v07 formats, and a set of UUIDs for v08 and beyond\&. Accepts the same syntax as in the
\fBget\-gi\fR
output\&. DRBD version 9\&.0\&.0 and beyond support multiple peers; use the
\fI\-\-node\-id\fR
option to define which peer\*(Aqs data generation identifiers to set\&.
.RE
.PP
\fBrestore\-md\fR \fIdump_file\fR
.RS 4

Replace the metadata on the device with the contents of
\fIdump_file\fR\&. The dump file format is defined by the output of the
\fBdump\-md\fR
command\&.
.RE
.SH "VERSION"
.sp
This document was revised for version 9\&.0\&.0 of the DRBD distribution\&.
.SH "AUTHOR"
.sp
Written by Philipp Reisner <philipp\&.reisner@linbit\&.com> and Lars Ellenberg <lars\&.ellenberg@linbit\&.com>\&.
.SH "REPORTING BUGS"
.sp
Report bugs to <drbd\-user@lists\&.linbit\&.com>\&.
.SH "COPYRIGHT"
.sp
Copyright 2001\-2008,2012 LINBIT Information Technologies, Philipp Reisner, Lars Ellenberg\&. This is free software; see the source for copying conditions\&. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE\&.
.SH "SEE ALSO"
.PP
\fBdrbdadm\fR(8)
\fBdrbd.conf\fR(5)