diff options
author | Theo de Raadt <deraadt@cvs.openbsd.org> | 2011-10-06 20:49:30 +0000 |
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committer | Theo de Raadt <deraadt@cvs.openbsd.org> | 2011-10-06 20:49:30 +0000 |
commit | 0647d56dd089f299d35587686681e19ad074627d (patch) | |
tree | 0bd77a196ba8c5bf639b51b50f88745e18caeec0 /share/man/man4/ccd.4 | |
parent | a4b88cea1f45014461763fd53d46221663687d94 (diff) |
ccd goes to the attic
discussed with jsing and millert
Diffstat (limited to 'share/man/man4/ccd.4')
-rw-r--r-- | share/man/man4/ccd.4 | 148 |
1 files changed, 0 insertions, 148 deletions
diff --git a/share/man/man4/ccd.4 b/share/man/man4/ccd.4 deleted file mode 100644 index 453fc661f89..00000000000 --- a/share/man/man4/ccd.4 +++ /dev/null @@ -1,148 +0,0 @@ -.\" $OpenBSD: ccd.4,v 1.23 2007/05/31 19:19:49 jmc Exp $ -.\" $NetBSD: ccd.4,v 1.5 1995/10/09 06:09:09 thorpej Exp $ -.\" -.\" Copyright (c) 1994 Jason Downs. -.\" Copyright (c) 1994, 1995 Jason R. Thorpe. -.\" All rights reserved. -.\" -.\" Redistribution and use in source and binary forms, with or without -.\" modification, are permitted provided that the following conditions -.\" are met: -.\" 1. Redistributions of source code must retain the above copyright -.\" notice, this list of conditions and the following disclaimer. -.\" 2. Redistributions in binary form must reproduce the above copyright -.\" notice, this list of conditions and the following disclaimer in the -.\" documentation and/or other materials provided with the distribution. -.\" 3. All advertising materials mentioning features or use of this software -.\" must display the following acknowledgement: -.\" This product includes software developed for the NetBSD Project -.\" by Jason Downs and Jason R. Thorpe. -.\" 4. Neither the name of the author nor the names of its contributors -.\" may be used to endorse or promote products derived from this software -.\" without specific prior written permission. -.\" -.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR -.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES -.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. -.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, -.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, -.\" BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; -.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED -.\" AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, -.\" OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY -.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF -.\" SUCH DAMAGE. -.\" -.Dd $Mdocdate: May 31 2007 $ -.Dt CCD 4 -.Os -.Sh NAME -.Nm ccd -.Nd concatenated disk driver -.Sh SYNOPSIS -.Cd "pseudo-device ccd" Op Ar count -.Sh DESCRIPTION -The -.Nm -driver provides the capability of combining one or more disks/partitions -into one virtual disk. -.Pp -Note that the -.Sq raw -partitions of the disks -.Em should not -be combined. -Each component partition should be offset at least one -cylinder from the beginning of the component disk. -This avoids potential conflicts between the component disk's -.Xr disklabel 8 -and the concatenated disk's disklabel. -The kernel wants to only allow component partitions of type -.Dv FS_CCD , -but due to disklabel restrictions on some architectures will also accept -component partitions of -.Dv FS_BSDFFS . -.Pp -In order to compile in support for -.Nm , -make sure your kernel configuration file contains a line -similar to the following (GENERIC does by default): -.Bd -literal -offset indent -pseudo-device ccd 4 # concatenated disk devices -.Ed -.Pp -The optional -.Ar count -argument specifies how many -concatenated disk devices are allocated for at boot time. -In this example, no more than 4 -may be configured. -.Pp -A -.Nm -may be either serially concatenated, interleaved, or mirrored. -To serially concatenate partitions, specify an interleave factor of 0. -Mirroring configurations require an even number of components. -.Pp -If a -.Nm -is interleaved correctly, a -.Dq striping -effect is achieved, which can increase performance. -Finding the optimum interleave factor is a hard problem. -Some things to think about are the number of disks in the -.Nm , -the typical read-ahead opportunities, the filesystem blocksize, and if -it's possible to use the optimized -.Nm -I/O protocol. -The optimized protocol allows smaller interleave factors for a -comparably cheap price but requires that the factor be a multiple of the -software page size -.Pf ( Dv CLBYTES ) , -and that mirroring is not requested. -So far the best policy is to test with different interleaves and -benchmark typical uses. -A rule of thumb might be to use the software pagesize with the optimized -I/O protocol (the default, unless the requirements mentioned above are not -fulfilled) or -.Dv MAXBSIZE / -#components with the unoptimized protocol. -Since the interleave factor is expressed in units of -.Dv DEV_BSIZE , -one must account for sector sizes other than -.Dv DEV_BSIZE -in order to calculate the correct interleave. -The kernel will not allow an interleave factor less than the size -of the largest component sector divided by -.Dv DEV_BSIZE . -.Pp -Note that best performance is achieved if all component disks have the same -geometry and size. -Optimum striping cannot occur with different disk types. -.Pp -There is a run-time utility that is used for configuring concatenated disks. -See -.Xr ccdconfig 8 -for more information. -.Sh FILES -.Bl -tag -width tenletters+five -compact -.It Pa /dev/{,r}ccd* -ccd device special files -.El -.Sh SEE ALSO -.Xr MAKEDEV 8 , -.Xr ccdconfig 8 , -.Xr disklabel 8 , -.Xr fsck 8 , -.Xr growfs 8 , -.Xr mount 8 , -.Xr newfs 8 -.Sh HISTORY -The concatenated disk driver was originally written at the University of -Utah. -.Sh CAVEATS -If just one (or more) of the disks in a -non-redundant -.Nm -configuration fails, the entire file system will be lost. |