.\"-
.\" Copyright (c) 2007 Dag-Erling Smørgrav
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
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.\" $FreeBSD$
.\"
.Dd March 20, 2007
.Dt NDR 1
.Os
.Sh NAME
.Nm ndr
.Nd network-assisted disk recovery
.Sh SYNOPSIS
.Nm
.Op Fl v
.Op Fl a Ar addr
.Op Fl d Ar dir
.Op Fl p Ar port
.Fl s
.Nm
.Op Fl v
.Op Fl a Ar addr
.Op Fl p Ar port
.Fl c
.Ar device
.Ar host
.Op Ar port
.Sh DESCRIPTION
The
.Nm
utility attempts to recover the contents of a damaged disk over the
network.
One instance of
.Nm
runs in client mode on the machine to which the damaged disk is
attached.
Another instance runs in server mode on a separate machine.
.Pp
When the client contacts the server and announces the device which is
to be recovered, the server creates a file of the appropriate size and
starts requesting blocks of data from the client.
As recovery progresses, the server keeps track of recovered and failed
blocks in a separate file.
Thus, both the server and the client can be interrupted and restarted
without losing progress.
This is particularly useful when a disk is so badly damaged that the
client machine crashes during recovery.
.Pp
The following options are available:
.Bl -tag -width Fl
.It Fl a Ar addr
Bind to the specified address.
.It Fl c
Work in client mode.
The name of the device to recover, the name or address of the server,
and (optionally) the server's port number must be specified on the
command line after all other options.
.It Fl d Ar dir
In server mode, work from the specified directory.
For each client that connects to the server, a subdirectory named
after the IP address of the client is created within the working
directory.
The data and map files for each device are stored in directories named
after the device within each client directory.
.It Fl p Ar port
Bind to the specified port.
.It Fl s
Work in server mode.
.It Fl v
Increase the verbosity level.
Specifying this option more than once may result in overwhelming
amounts of debugging output.
.El
.Sh EXAMPLES
Start a server which will listen on port 6543 at the address
corresponding to
.Pa ndr.example.com ,
store the data it receives in
.Pa /var/ndr ,
and show a moderate amount of debugging information:
.Bd -literal -offset indent
ndr -s -a ndr.example.com -p 6543 -d /var/ndr -v
.Ed
.Pp
Start a client which will transfer the contents of
.Pa /dev/ad4
to the server running on port 6543 on
.Pa ndr.example.com :
.Bd -literal -offset indent
ndr -c /dev/ad4 ndr.example.com 6543
.Ed
.Pp
The following
.Xr hexdump 1
command line displays the contents of a map file:
.Bd -literal -offset indent
hexdump -v -e '"%07.7_ax " 64/1 "%_c" "\\n"' map
.Ed
.Pp
Each output line starts with a hexadecimal offset followed by 64 ASCII
characters, each representing one block of the device.
Successfully recovered blocks are marked with a hash sign.
Blocks which have failed but will be retried are marked with a digit
reflecting the number of attempts that have been made.
Blocks which
.Nm
has given up on are marked with an asterisk.
.Sh AUTHORS
.An -nosplit
The
.Nm
utility and this manual page were written by
.An Dag-Erling Sm\(/orgrav Aq des@FreeBSD.org .