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.Nm 45.Fl C 46.Op Fl v 47.Op Fl f Ar config_file 48.Nm 49.Fl u 50.Op Fl v 51.Ar ccd ... 52.Nm 53.Fl U 54.Op Fl v 55.Op Fl f Ar config_file 56.Nm 57.Fl g 58.Op Ar ccd ... 59.Sh DESCRIPTION 60The 61.Nm 62utility is used to dynamically configure and unconfigure concatenated disk 63devices, or ccds. 64For more information about the ccd, see 65.Xr ccd 4 . 66.Pp 67The options are as follows: 68.Bl -tag -width indent 69.It Fl c 70Configure a ccd. 71This is the default behavior of 72.Nm . 73.It Fl C 74Configure all ccd devices listed in the ccd configuration file. 75.It Fl f Ar config_file 76When configuring or unconfiguring all devices, read the file 77.Pa config_file 78instead of the default 79.Pa /etc/ccd.conf . 80.It Fl g 81Dump the current ccd configuration in a format suitable for use as the 82ccd configuration file. 83If no arguments are specified, every configured 84ccd is dumped. 85Otherwise, the configuration of each listed ccd is dumped. 86.It Fl u 87Unconfigure a ccd. 88.It Fl U 89Unconfigure all ccd devices listed the ccd configuration file. 90.It Fl v 91Cause 92.Nm 93to be verbose. 94.El 95.Pp 96A ccd is described on the command line and in the ccd configuration 97file by the name of the ccd, the interleave factor, the ccd configuration 98flags, and a list of one or more devices. 99The flags may be represented 100as a decimal number, a hexadecimal number, a comma-separated list 101of strings, or the word 102.Dq none . 103The flags are as follows: 104.Bd -literal -offset indent 105CCDF_UNIFORM 0x02 Use uniform interleave 106CCDF_MIRROR 0x04 Support mirroring 107.Ed 108.Pp 109The format in the 110configuration file appears exactly as if it were entered on the command line. 111Note that on the command line and in the configuration file, the 112.Pa flags 113argument is optional. 114.Bd -literal -offset indent 115# 116# /etc/ccd.conf 117# Configuration file for concatenated disk devices 118# 119 120# ccd ileave flags component devices 121ccd0 16 none /dev/da2s1 /dev/da3s1 122.Ed 123.Pp 124The component devices need to name partitions of type 125.Li FS_BSDFFS 126(or 127.Dq 4.2BSD 128as shown by 129.Xr disklabel 8 ) . 130.Sh FILES 131.Bl -tag -width /etc/ccd.conf -compact 132.It Pa /etc/ccd.conf 133default ccd configuration file 134.El 135.Sh EXAMPLES 136A number of 137.Nm 138examples are shown below. 139The arguments passed 140to 141.Nm 142are exactly the same as you might place in the 143.Pa /etc/ccd.conf 144configuration file. 145The first example creates a 4-disk stripe out of 146four scsi disk partitions. 147The stripe uses a 64 sector interleave. 148The second example is an example of a complex stripe/mirror combination. 149It reads as a two disk stripe of da4 and da5 which is mirrored 150to a two disk stripe of da6 and da7. 151The last example is a simple 152mirror. 153The 2nd slice of /dev/da8 is mirrored with the 3rd slice of /dev/da9 154and assigned to ccd0. 155.Pp 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 162When you create a new ccd disk you generally want to 163.Xr fdisk 8 164and 165.Xr disklabel 8 166it before doing anything else. 167Once you create the initial label you can 168edit it, adding additional partitions. 169The label itself takes up the first 17016 sectors of the ccd disk. 171If all you are doing is creating file systems 172with newfs, you do not have to worry about this as newfs will skip the 173label area. 174However, if you intend to 175.Xr dd 1 176to or from a ccd partition it is usually a good idea to construct the 177partition such that it does not overlap the label area. 178For example, if 179you have A ccd disk with 10000 sectors you might create a 'd' partition 180with offset 16 and size 9984. 181.Pp 182.Bd -literal 183# disklabel ccd0 > /tmp/disklabel.ccd0 184# disklabel -Rr ccd0 /tmp/disklabel.ccd0 185# disklabel -e ccd0 186.Ed 187.Pp 188The disklabeling of a ccd disk is usually a one-time affair. 189If you reboot the machine and reconfigure the ccd disk, 190the disklabel you 191had created before will still be there and not require reinitialization. 192Beware that changing any ccd parameters: interleave, flags, or the 193device list making up the ccd disk, will usually destroy any prior 194data on that ccd disk. 195If this occurs it is usually a good idea to 196reinitialize the label before [re]constructing your ccd disk. 197.Sh RECOVERY 198An error on a ccd disk is usually unrecoverable unless you are using the 199mirroring option. 200But mirroring has its own perils: It assumes that 201both copies of the data at any given sector are the same. 202This holds true 203until a write error occurs or until you replace either side of the mirror. 204This is a poor-man's mirroring implementation. 205It works well enough that if 206you begin to get disk errors you should be able to backup the ccd disk, 207replace the broken hardware, and then regenerate the ccd disk. 208If you need 209more than this you should look into external hardware RAID SCSI boxes, 210RAID controllers (see GENERIC), 211or software RAID systems such as 212.Xr geom 8 213and 214.Xr vinum 8 . 215.Sh SEE ALSO 216.Xr dd 1 , 217.Xr ccd 4 , 218.Xr raid 4 , 219.Xr disklabel 8 , 220.Xr fdisk 8 , 221.Xr rc 8 , 222.Xr vinum 8 223.Sh HISTORY 224The 225.Nm 226utility first appeared in 227.Nx 1.0a . 228.Sh BUGS 229The initial disklabel returned by 230.Xr ccd 4 231specifies only 3 partitions. 232One needs to change the number of paritions to 8 using 233.Dq Nm disklabel Fl e 234to get the usual 235.Bx 236expectations. 237