1.\" Copyright (c) 1996 The NetBSD Foundation, Inc. 2.\" All rights reserved. 3.\" 4.\" This code is derived from software contributed to The NetBSD Foundation 5.\" by Jason R. Thorpe. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 21.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 22.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 23.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 24.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" $NetBSD: ccdconfig.8,v 1.4 1996/02/28 01:01:17 thorpej Exp $ 29.\" 30.Dd March 22, 2024 31.Dt CCDCONFIG 8 32.Os 33.Sh NAME 34.Nm ccdconfig 35.Nd configuration utility for the concatenated disk driver 36.Sh SYNOPSIS 37.Nm 38.Op Fl cv 39.Ar ccd 40.Ar ileave 41.Op Ar flags 42.Ar dev ... 43.Nm 44.Fl C 45.Op Fl v 46.Op Fl f Ar config_file 47.Nm 48.Fl u 49.Op Fl v 50.Ar ccd ... 51.Nm 52.Fl U 53.Op Fl v 54.Op Fl f Ar config_file 55.Nm 56.Fl g 57.Op Ar ccd ... 58.Sh DESCRIPTION 59The 60.Nm 61utility is used to dynamically configure and unconfigure concatenated disk 62devices, or ccds. 63For more information about the ccd, see 64.Xr ccd 4 . 65.Pp 66The options are as follows: 67.Bl -tag -width indent 68.It Fl c 69Configure a ccd. 70This is the default behavior of 71.Nm . 72.It Fl C 73Configure all ccd devices listed in the ccd configuration file. 74.It Fl f Ar config_file 75When configuring or unconfiguring all devices, read the file 76.Pa config_file 77instead of the default 78.Pa /etc/ccd.conf . 79.It Fl g 80Dump the current ccd configuration in a format suitable for use as the 81ccd configuration file. 82If no arguments are specified, every configured 83ccd is dumped. 84Otherwise, the configuration of each listed ccd is dumped. 85.It Fl u 86Unconfigure a ccd. 87.It Fl U 88Unconfigure all ccd devices listed the ccd configuration file. 89.It Fl v 90Cause 91.Nm 92to be verbose. 93.El 94.Pp 95A ccd is described on the command line and in the ccd configuration 96file by the name of the ccd, the interleave factor, the ccd configuration 97flags, and a list of one or more devices. 98The flags may be represented 99as a decimal number, a hexadecimal number, a comma-separated list 100of strings, or the word 101.Dq none . 102The flags are as follows: 103.Bd -literal -offset indent 104CCDF_UNIFORM 0x02 Use uniform interleave 105CCDF_MIRROR 0x04 Support mirroring 106CCDF_NO_OFFSET 0x08 Do not use an offset 107CCDF_LINUX 0x0A Linux md(4) compatibility 108.Ed 109.Pp 110The format in the 111configuration file appears exactly as if it were entered on the command line. 112Note that on the command line and in the configuration file, the 113.Pa flags 114argument is optional. 115.Bd -literal -offset indent 116# 117# /etc/ccd.conf 118# Configuration file for concatenated disk devices 119# 120 121# ccd ileave flags component devices 122ccd0 16 none /dev/da2s1 /dev/da3s1 123.Ed 124.Pp 125If you want to use the 126.Tn Linux 127.Xr md 4 128compatibility mode, please be sure 129to read the notes in 130.Xr ccd 4 . 131.Sh FILES 132.Bl -tag -width /etc/ccd.conf -compact 133.It Pa /etc/ccd.conf 134default ccd configuration file 135.El 136.Sh EXAMPLES 137A number of 138.Nm 139examples are shown below. 140The arguments passed 141to 142.Nm 143are exactly the same as you might place in the 144.Pa /etc/ccd.conf 145configuration file. 146The first example creates a 4-disk stripe out of 147four scsi disk partitions. 148The stripe uses a 64-sector interleave. 149The second example is an example of a complex stripe/mirror combination. 150It reads as a two disk stripe of da4 and da5 which is mirrored 151to a two disk stripe of da6 and da7. 152The last example is a simple 153mirror. 154The second slice of /dev/da8 is mirrored with the third slice of /dev/da9 155and assigned to ccd0. 156.Bd -literal 157# ccdconfig ccd0 64 none /dev/da0s1 /dev/da1s1 /dev/da2s1 /dev/da3s1 158# ccdconfig ccd0 128 CCDF_MIRROR /dev/da4 /dev/da5 /dev/da6 /dev/da7 159# ccdconfig ccd0 128 CCDF_MIRROR /dev/da8s2 /dev/da9s3 160.Ed 161.Pp 162The following are matching commands in 163.Tn Linux 164and 165.Fx 166to create a RAID-0 in 167.Tn Linux 168and read it from 169.Fx . 170.Bd -literal 171# Create a RAID-0 on Linux: 172mdadm --create --chunk=32 --level=0 --raid-devices=2 /dev/md0 \\ 173 /dev/hda1 /dev/hdb1 174# Make the RAID-0 just created available on FreeBSD: 175ccdconfig -c /dev/ccd0 32 linux /dev/ada0s1 /dev/ada0s2 176.Ed 177.Pp 178When you create a new ccd disk you generally want to 179partition it using 180.Xr gpart 8 181it before doing anything else. 182Beware that changing any ccd parameters: interleave, flags, or the 183device list making up the ccd disk, will usually destroy any prior 184data on that ccd disk. 185If this occurs it is usually a good idea to 186reinitialize the label before [re]constructing your ccd disk. 187.Sh RECOVERY 188An error on a ccd disk is usually unrecoverable unless you are using the 189mirroring option. 190But mirroring has its own perils: It assumes that 191both copies of the data at any given sector are the same. 192This holds true 193until a write error occurs or until you replace either side of the mirror. 194This is a poor-man's mirroring implementation. 195It works well enough that if 196you begin to get disk errors you should be able to backup the ccd disk, 197replace the broken hardware, and then regenerate the ccd disk. 198If you need 199more than this you should look into external hardware RAID SCSI boxes, 200RAID controllers (see GENERIC), 201or software RAID systems such as 202.Xr geom 8 203and 204.Xr gvinum 8 . 205.Sh SEE ALSO 206.Xr dd 1 , 207.Xr ccd 4 , 208.Xr gpart 8 , 209.Xr gvinum 8 , 210.Xr rc 8 211.Sh HISTORY 212The 213.Nm 214utility first appeared in 215.Nx 1.1 . 216