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 66The 67.Nm 68utility is used to dynamically configure and unconfigure concatenated disk 69devices, or ccds. For more information about the ccd, see 70.Xr ccd 4 . 71.Pp 72The options are as follows: 73.Bl -tag -width indent 74.It Fl c 75Configure a ccd. This is the default behavior of 76.Nm . 77.It Fl C 78Configure all ccd devices listed in the ccd configuration file. 79.It Fl f Ar config_file 80When configuring or unconfiguring all devices, read the file 81.Pa config_file 82instead of the default 83.Pa /etc/ccd.conf . 84.It Fl g 85Dump the current ccd configuration in a format suitable for use as the 86ccd configuration file. If no arguments are specified, every configured 87ccd is dumped. Otherwise, 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. The flags may be represented 101as a decimal number, a hexadecimal number, a comma-separated list 102of strings, or the word 103.Dq none . 104The flags are as follows: 105.Bd -unfilled -offset indent 106CCDF_SWAP 0x01 Interleave should be dmmax 107CCDF_UNIFORM 0x02 Use uniform interleave 108CCDF_MIRROR 0x04 Support mirroring 109CCDF_PARITY 0x08 Support parity (not implemented yet) 110.Ed 111.Pp 112The format in the 113configuration file appears exactly as if it were entered on the command line. 114Note that on the command line and in the configuration file, the 115.Pa flags 116argument is optional. 117.Bd -unfilled -offset indent 118# 119# /etc/ccd.conf 120# Configuration file for concatenated disk devices 121# 122.Pp 123# ccd ileave flags component devices 124ccd0 16 none /dev/da2e /dev/da3e 125.Ed 126.Pp 127The component devices need to name partitions of type 128.Li FS_BSDFFS 129(or 130.Dq 4.2BSD 131as shown by 132.Xr disklabel 8 ) . 133.Sh EXAMPLES 134A number of 135.Nm 136examples are shown below. The arguments passed 137to 138.Nm 139are exactly the same as you might place in the 140.Pa /etc/ccd.conf 141configuration file. The first example creates a 4-disk stripe out of 142four scsi disk partitions. The stripe uses a 64 sector interleave. 143The second example is an example of a complex stripe/mirror combination. 144It reads as a two disk stripe of da2e and da3e which is mirrored 145to a two disk stripe of da4e and da5e. The last example is a simple 146mirror. /dev/da2e is mirrored with /dev/da4e and assigned to ccd0. 147.Pp 148.Bd -unfilled -offset 149# ccdconfig ccd0 64 none /dev/da2e /dev/da3e /dev/da4e /dev/da5e 150# ccdconfig ccd0 128 CCDF_MIRROR /dev/da2e /dev/da3e /dev/da4e /dev/da5e 151# ccdconfig ccd0 128 CCDF_MIRROR /dev/da2e /dev/da4e 152.Ed 153.Pp 154When you create a new ccd disk you generally want to 155.Nm disklabel 156it before doing anything else. Once you create the initial label you can 157edit it, adding additional partitions. The label itself takes up the first 15816 sectors of the ccd disk. If all you are doing is creating filesystems 159with newfs, you do not have to worry about this as newfs will skip the 160label area. However, if you intend to 161.Nm dd 162to or from a ccd partition it is usually a good idea to construct the 163partition such that it does not overlap the label area. For example, if 164you have A ccd disk with 10000 sectors you might create a 'd' partition 165with offset 16 and size 9984. 166.Pp 167.Bd -unfilled -offset 168# disklabel -r -w ccd0c auto 169# disklabel -e ccd0c 170.Ed 171.Pp 172The disklabeling of a ccd disk is usually a one-time affair. Unlike other 173devices, ccd currently requires that you specify partition 'c' when 174running disklabel. If you reboot the machine and reconfigure the ccd disk, 175the disklabel you 176had created before will still be there and not require reinitialization. 177Beware that changing any ccd parameters: interleave, flags, or the 178device list making up the ccd disk, will usually destroy any prior 179data on that ccd disk. If this occurs it is usually a good idea to 180reinitialize the label before [re]constructing your ccd disk. 181.Sh RECOVERY 182An error on a ccd disk is usually unrecoverable unless you are using the 183mirroring option. But mirroring has its own perils: It assumes that 184both copies of the data at any given sector are the same. This holds true 185until a write error occurs or until you replace either side of the mirror. 186This is a poor-man's mirroring implementation. It works well enough that if 187you begin to get disk errors you should be able to backup the ccd disk, 188replace the broken hardware, and then regenerate the ccd disk. If you need 189more than this you should look into external hardware RAID SCSI boxes, 190RAID controllers such as the 191.Nm dpt 192controller, or software RAID systems such as 193.Nm vinum . 194.Sh FILES 195.Bl -tag -width /etc/ccd.conf -compact 196.It Pa /etc/ccd.conf 197default ccd configuration file 198.El 199.Sh SEE ALSO 200.Xr ccd 4 , 201.Xr rc 8 , 202.Xr vinum 8 203.Sh HISTORY 204The 205.Nm 206utility first appeared in 207.Nx 1.0a . 208