xref: /freebsd/sbin/ccdconfig/ccdconfig.8 (revision ae83180158c4c937f170e31eff311b18c0286a93)
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.
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16.\"	This product includes software developed for the NetBSD Project
17.\"	by Jason R. Thorpe.
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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