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.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgment: 16.\" This product includes software developed for the NetBSD Project 17.\" by Jason R. Thorpe. 18.\" 4. The name of the author may not be used to endorse or promote products 19.\" derived from this software without specific prior written permission. 20.\" 21.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 27.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31.\" SUCH DAMAGE. 32.\" 33.\" $FreeBSD$ 34.\" 35.Dd July 17, 1995 36.Dt CCDCONFIG 8 37.Os 38.Sh NAME 39.Nm ccdconfig 40.Nd configuration utility for the concatenated disk driver 41.Sh SYNOPSIS 42.Nm 43.Op Fl cv 44.Ar ccd 45.Ar ileave 46.Op Ar flags 47.Ar dev 48.Op Ar 49.Nm 50.Fl C 51.Op Fl v 52.Op Fl f Ar config_file 53.Nm 54.Fl u 55.Op Fl v 56.Ar ccd 57.Op Ar 58.Nm 59.Fl U 60.Op Fl v 61.Op Fl f Ar config_file 62.Nm 63.Fl g 64.Op Ar ccd Op Ar ... 65.Sh DESCRIPTION 66.Nm Ccdconfig 67is used to dynamically configure and unconfigure concatenated disk 68devices, or ccds. For more information about the ccd, see 69.Xr ccd 4 . 70.Pp 71The options are as follows: 72.Bl -tag -width indent 73.It Fl c 74Configure a ccd. This is the default behavior of 75.Nm . 76.It Fl C 77Configure all ccd devices listed in the ccd configuration file. 78.It Fl f Ar config_file 79When configuring or unconfiguring all devices, read the file 80.Pa config_file 81instead of the default 82.Pa /etc/ccd.conf . 83.It Fl g 84Dump the current ccd configuration in a format suitable for use as the 85ccd configuration file. If no arguments are specified, every configured 86ccd is dumped. Otherwise, the configuration of each listed ccd is dumped. 87.It Fl u 88Unconfigure a ccd. 89.It Fl U 90Unconfigure all ccd devices listed the ccd configuration file. 91.It Fl v 92Cause 93.Nm 94to be verbose. 95.El 96.Pp 97A ccd is described on the command line and in the ccd configuration 98file by the name of the ccd, the interleave factor, the ccd configuration 99flags, and a list of one or more devices. The 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 -unfilled -offset indent 105CCDF_SWAP 0x01 Interleave should be dmmax 106CCDF_UNIFORM 0x02 Use uniform interleave 107CCDF_MIRROR 0x04 Support mirroring 108CCDF_PARITY 0x08 Support parity (not implemented yet) 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 -unfilled -offset indent 117# 118# /etc/ccd.conf 119# Configuration file for concatenated disk devices 120# 121.Pp 122# ccd ileave flags component devices 123ccd0 16 none /dev/da2e /dev/da3e 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 EXAMPLES 133A number of ccdconfig examples are shown below. The arguments passed 134to ccdconfig are exactly the same as you might place in the 135.Pa /etc/ccd.conf 136configuration file. The first example creates a 4-disk stripe out of 137four scsi disk partitions. The stripe uses a 64 sector interleave. 138The second example is an example of a complex stripe/mirror combination. 139It reads as a two disk stripe of da2e and da3e which is mirrored 140to a two disk stripe of da4e and da5e. The last example is a simple 141mirror. /dev/da2e is mirrored with /dev/da4e and assigned to ccd0. 142.Pp 143.Bd -unfilled -offset 144# ccdconfig ccd0 64 none /dev/da2e /dev/da3e /dev/da4e /dev/da5e 145# ccdconfig ccd0 128 CCDF_MIRROR /dev/da2e /dev/da3e /dev/da4e /dev/da5e 146# ccdconfig ccd0 128 CCDF_MIRROR /dev/da2e /dev/da4e 147.Ed 148.Pp 149When you create a new ccd disk you generally want to 150.Nm disklabel 151it before doing anything else. Once you create the initial label you can 152edit it, adding additional partitions. The label itself takes up the first 15316 sectors of the ccd disk. If all you are doing is creating filesystems 154with newfs, you do not have to worry about this as newfs will skip the 155label area. However, if you intend to 156.Nm dd 157to or from a ccd partition it is usually a good idea to construct the 158partition such that it does not overlap the label area. For example, if 159you have A ccd disk with 10000 sectors you might create a 'd' partition 160with offset 16 and size 9984. 161.Pp 162.Bd -unfilled -offset 163# disklabel -r -w ccd0c auto 164# disklabel -e ccd0c 165.Ed 166.Pp 167The disklabeling of a ccd disk is usually a one-time affair. Unlike other 168devices, ccd currently requires that you specify partition 'c' when 169running disklabel. If you reboot the machine and reconfigure the ccd disk, 170the disklabel you 171had created before will still be there and not require reinitialization. 172Beware that changing any ccd parameters: interleave, flags, or the 173device list making up the ccd disk, will usually destroy any prior 174data on that ccd disk. If this occurs it is usually a good idea to 175reinitialize the label before [re]constructing your ccd disk. 176.Sh RECOVERY 177An error on a ccd disk is usually unrecoverable unless you are using the 178mirroring option. But mirroring has its own perils: It assumes that 179both copies of the data at any given sector are the same. This holds true 180until a write error occurs or until you replace either side of the mirror. 181.Nm Ccd 182uses a poor-man's mirroring implementation. It works well enough that if 183you begin to get disk errors you should be able to backup the ccd disk, 184replace the broken hardware, and then regenerate the ccd disk. If you need 185more then this you should look into external hardware RAID SCSI boxes, 186RAID controllers such as the 187.Nm dpt 188controller, or software RAID systems such as 189.Nm vinum . 190.Sh FILES 191.Bl -tag -width /etc/ccd.conf -compact 192.It Pa /etc/ccd.conf 193default ccd configuration file 194.El 195.Sh SEE ALSO 196.Xr ccd 4 , 197.Xr rc 8 , 198.Xr vinum 8 199.Sh HISTORY 200The 201.Nm 202command first appeared in 203.Nx 1.0a . 204