1.\" $NetBSD: ccdconfig.8,v 1.1.2.1 1995/11/11 02:43:33 thorpej Exp $ 2.\" 3.\" Copyright (c) 1995 Jason R. Thorpe. 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 4. The name of the author may not be used to endorse or promote products 15.\" derived from this software without specific prior written permission. 16.\" 17.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 22.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 23.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 24.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 25.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27.\" SUCH DAMAGE. 28.\" 29.\" $FreeBSD$ 30.\" 31.Dd July 17, 1995 32.Dt CCDCONFIG 8 33.Os 34.Sh NAME 35.Nm ccdconfig 36.Nd configuration utility for the concatenated disk driver 37.Sh SYNOPSIS 38.Nm 39.Op Fl cv 40.Ar ccd 41.Ar ileave 42.Op Ar flags 43.Ar dev 44.Op Ar 45.Nm 46.Fl C 47.Op Fl v 48.Op Fl f Ar config_file 49.Nm 50.Fl u 51.Op Fl v 52.Ar ccd 53.Op Ar 54.Nm 55.Fl U 56.Op Fl v 57.Op Fl f Ar config_file 58.Nm 59.Fl g 60.Op Ar ccd Op Ar ... 61.Sh DESCRIPTION 62The 63.Nm 64utility is used to dynamically configure and unconfigure concatenated disk 65devices, or ccds. 66For more information about the ccd, see 67.Xr ccd 4 . 68.Pp 69The options are as follows: 70.Bl -tag -width indent 71.It Fl c 72Configure a ccd. 73This is the default behavior of 74.Nm . 75.It Fl C 76Configure all ccd devices listed in the ccd configuration file. 77.It Fl f Ar config_file 78When configuring or unconfiguring all devices, read the file 79.Pa config_file 80instead of the default 81.Pa /etc/ccd.conf . 82.It Fl g 83Dump the current ccd configuration in a format suitable for use as the 84ccd configuration file. 85If no arguments are specified, every configured 86ccd is dumped. 87Otherwise, the configuration of each listed ccd is dumped. 88.It Fl u 89Unconfigure a ccd. 90.It Fl U 91Unconfigure all ccd devices listed the ccd configuration file. 92.It Fl v 93Cause 94.Nm 95to be verbose. 96.El 97.Pp 98A ccd is described on the command line and in the ccd configuration 99file by the name of the ccd, the interleave factor, the ccd configuration 100flags, and a list of one or more devices. 101The flags may be represented 102as a decimal number, a hexadecimal number, a comma-separated list 103of strings, or the word 104.Dq none . 105The flags are as follows: 106.Bd -literal -offset indent 107CCDF_UNIFORM 0x02 Use uniform interleave 108CCDF_MIRROR 0x04 Support mirroring 109.Ed 110.Pp 111The format in the 112configuration file appears exactly as if it were entered on the command line. 113Note that on the command line and in the configuration file, the 114.Pa flags 115argument is optional. 116.Bd -literal -offset indent 117# 118# /etc/ccd.conf 119# Configuration file for concatenated disk devices 120# 121 122# ccd ileave flags component devices 123ccd0 16 none /dev/da2s1 /dev/da3s1 124.Ed 125.Pp 126The component devices need to name partitions of type 127.Li FS_BSDFFS 128(or 129.Dq 4.2BSD 130as shown by 131.Xr disklabel 8 ) . 132.Sh FILES 133.Bl -tag -width /etc/ccd.conf -compact 134.It Pa /etc/ccd.conf 135default ccd configuration file 136.El 137.Sh EXAMPLES 138A number of 139.Nm 140examples are shown below. 141The arguments passed 142to 143.Nm 144are exactly the same as you might place in the 145.Pa /etc/ccd.conf 146configuration file. 147The first example creates a 4-disk stripe out of 148four scsi disk partitions. 149The stripe uses a 64 sector interleave. 150The second example is an example of a complex stripe/mirror combination. 151It reads as a two disk stripe of da4 and da5 which is mirrored 152to a two disk stripe of da6 and da7. 153The last example is a simple 154mirror. 155The 2nd slice of /dev/da8 is mirrored with the 3rd slice of /dev/da9 156and assigned to ccd0. 157.Pp 158.Bd -literal 159# ccdconfig ccd0 64 none /dev/da0s1 /dev/da1s1 /dev/da2s1 /dev/da3s1 160# ccdconfig ccd0 128 CCDF_MIRROR /dev/da4 /dev/da5 /dev/da6 /dev/da7 161# ccdconfig ccd0 128 CCDF_MIRROR /dev/da8s2 /dev/da9s3 162.Ed 163.Pp 164When you create a new ccd disk you generally want to 165.Xr fdisk 8 166and 167.Xr disklabel 8 168it before doing anything else. 169Once you create the initial label you can 170edit it, adding additional partitions. 171The label itself takes up the first 17216 sectors of the ccd disk. 173If all you are doing is creating file systems 174with newfs, you do not have to worry about this as newfs will skip the 175label area. 176However, if you intend to 177.Xr dd 1 178to or from a ccd partition it is usually a good idea to construct the 179partition such that it does not overlap the label area. 180For example, if 181you have A ccd disk with 10000 sectors you might create a 'd' partition 182with offset 16 and size 9984. 183.Pp 184.Bd -literal 185# disklabel ccd0 > /tmp/disklabel.ccd0 186# disklabel -Rr ccd0 /tmp/disklabel.ccd0 187# disklabel -e ccd0 188.Ed 189.Pp 190The disklabeling of a ccd disk is usually a one-time affair. 191If you reboot the machine and reconfigure the ccd disk, 192the disklabel you 193had created before will still be there and not require reinitialization. 194Beware that changing any ccd parameters: interleave, flags, or the 195device list making up the ccd disk, will usually destroy any prior 196data on that ccd disk. 197If this occurs it is usually a good idea to 198reinitialize the label before [re]constructing your ccd disk. 199.Sh RECOVERY 200An error on a ccd disk is usually unrecoverable unless you are using the 201mirroring option. 202But mirroring has its own perils: It assumes that 203both copies of the data at any given sector are the same. 204This holds true 205until a write error occurs or until you replace either side of the mirror. 206This is a poor-man's mirroring implementation. 207It works well enough that if 208you begin to get disk errors you should be able to backup the ccd disk, 209replace the broken hardware, and then regenerate the ccd disk. 210If you need 211more than this you should look into external hardware RAID SCSI boxes, 212RAID controllers (see GENERIC), 213or software RAID systems such as 214.Xr geom 8 215and 216.Xr vinum 8 . 217.Sh SEE ALSO 218.Xr dd 1 , 219.Xr ccd 4 , 220.Xr raid 4 , 221.Xr disklabel 8 , 222.Xr fdisk 8 , 223.Xr rc 8 , 224.Xr vinum 8 225.Sh HISTORY 226The 227.Nm 228utility first appeared in 229.Nx 1.0a . 230.Sh BUGS 231The initial disklabel returned by 232.Xr ccd 4 233specifies only 3 partitions. 234One needs to change the number of paritions to 8 using 235.Dq Nm disklabel Fl e 236to get the usual 237.Bx 238expectations. 239