From owner-freebsd-stable Sat Apr 27 21:21:46 1996 Return-Path: owner-stable Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id VAA03586 for stable-outgoing; Sat, 27 Apr 1996 21:21:46 -0700 (PDT) Received: from nic.ott.hookup.net (uucp@nic.ott.hookup.net [165.154.5.1]) by freefall.freebsd.org (8.7.3/8.7.3) with ESMTP id VAA03581 for ; Sat, 27 Apr 1996 21:21:41 -0700 (PDT) Received: (uucp@localhost) by nic.ott.hookup.net (8.7.5/1.169) with UUCP id AAA08616; Sun, 28 Apr 1996 00:21:30 -0400 (EDT) Received: from cc:Mail UUCPLINK 2.0 by ccigate.acdi-cida.gc.ca id 9603288306.AA830675254 Sun, 28 Apr 96 00:07:34 Date: Sun, 28 Apr 96 00:07:34 From: administrator@ccigate.acdi-cida.gc.ca Message-Id: <9603288306.AA830675254@ccigate.acdi-cida.gc.ca> To: stable@FreeBSD.org Subject: ccd for 2.1-stable Subject: cc:Mail UUCPLINK 2.0 Undeliverable Message Sender: owner-stable@FreeBSD.org X-Loop: FreeBSD.org Precedence: bulk User ccigate!ccigate.acdi-cida.gc.ca!louis_gaulin@ccigate.acdi-cida.gc.ca is not defined Original text follows ----------------------------------------- Received: by ccmail Received: from hookup by acdi-cida.gc.ca (UUPC/extended 1.11) with UUCP; Sun, 28 Apr 1996 00:06:13 EDT Received: from freefall.freebsd.org (freefall.FreeBSD.ORG [204.216.27.4]) by nic.ott.hookup.net (8.7.5/1.169) with ESMTP id XAA23172 for ; Sat, 27 Apr 1996 23:23:32 -0400 (EDT) Received: from localhost (daemon@localhost) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id UAA28928 Sat, 27 Apr 1996 20:01:49 -0700 (PDT) Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id UAA28920 for freebsd-announce-outgoing; Sat, 27 Apr 1996 20:01:48 -0700 (PDT) Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id UAA28914 for freebsd-announce; Sat, 27 Apr 1996 20:01:44 -0700 (PDT) Date: Sat, 27 Apr 1996 20:01:44 -0700 (PDT) Message-Id: <199604280301.UAA28914@freefall.freebsd.org> Reply-to: stable@FreeBSD.org Subject: ccd for 2.1-stable From: asami@freefall.freebsd.org (Satoshi Asami) X-ccAdmin: postmaster@hookup To: announce@FreeBSD.org Sender: owner-freebsd-announce@FreeBSD.org X-Loop: FreeBSD.org Precedence: bulk Hello the disk world, I ported the 2.2-current version of ccd back to 2.1-stable. There is no change in functionality from the previous version. (It's just that it compiles now on your 2.1-stable machine. :) Satoshi P.S. Please check out "http://stampede.cs.berkeley.edu/ccd/" and "README-s.html" in that directory! ------- $Id: ccd.README,v 1.9.2.1 1996/04/27 07:08:43 asami Exp $ ********************************************************** * The FreeBSD ccd driver (beta) * * for 2.1-stable users * * by Satoshi Asami * * and Nisha Talagala * * version of 96/04/27 * ********************************************************** (0) Changes from previous versions (Jan/14, Jan/31, Mar/20, Mar/25) Jan/14 -> Jan/31: . There is mirroring support . ccdcontrol is renamed ccdconfig (back to original NetBSD name) . ccdconfig is now in /sbin (so you can call it from rc -- a patch to rc is also included) Jan/31 -> Mar/20: . It now runs under -current . ccd.c is moved from sys/ccd to sys/dev/ccd (like NetBSD) . The driver is now a proper pseudo-device (unlike the isa device like before, see below for kernel config file changes) Mar/20 -> Mar/25: . Mirror handling code is cleaner, and doesn't kludge around b_resid's anymore. For the implementation, read note near top of ccd.c. Mar/25 -> Apr/27: . Ported back from 2.2-current to 2.1-stable. No change in functionality. (1) Introduction This is a port of NetBSD's ccd (concatenated disk) driver. It is not a complete work in any way, but seems to be working fairly ok here, so we decided to make it available so that people can test it and even fix some bugs. :) (2) Warning As the title above says, this is beta software and is therefore VERY GREEN. You should not expect this to work. It may eat your system disk for lunch. It may even fry your microwave in the process. Make sure you have backed up all your data and locked your children in the basement before you attempt to try this. (3) What it does In case you don't know what it is, ccd is a disk array driver. You can combine several disk partitions into one "virtual disk". Then you can partition it or use the whole thing or add some pepper and salt or whatever you want. (4) What it does not There is no parity support yet. That's why its name doesn't resemble RAID in any form. However, there is mirroring available starting from the Jan/31 version. (4a) Cool, how do I use mirroring? Add CCDF_MIRROR to the list of flags (third field in /etc/ccd.conf), and your disk space will magically shrink into half. The writes go to all disks, while the reads will all come from the first n/2 disks. If one of the disk goes "poof", you can reconfigure the ccd to use only half the disks without mirroring. That should keep your users happy until you get the chance to put in the replacement disk. When the new disk is installed, use the ccd recovery program called `dd' (which mysteriously made its way into the release even before we put out an alpha version of ccd), e.g., to copy sd1g to sd4g, dd if=/dev/rsd1g of=/dev/rsd4g bs=1048576 (5) How to compile Note this package is for FreeBSD-current (aka 2.2-current). It probably won't work right away for 2.1R or 2.1-stable. It even may not work for your version of -current (depending on what date you got your source). Ok, first you need to unpack the distribution. It contains the following files: sys/dev/ccd/ccd.README (this file) sys/dev/ccd/ccd.PLIST sys/dev/ccd/ccd.4 sys/dev/ccd/ccd.c sys/sys/ccdvar.h sbin/ccdconfig/Makefile sbin/ccdconfig/ccdconfig.8 sbin/ccdconfig/ccdconfig.c sbin/ccdconfig/pathnames.h ccd.patch You can unpack them in your /usr/src directory. After that, apply the ccd.patch. It makes several changes to the header files and such. You can use the following command to apply the patch: patch -p < ccd.patch (On a separate line for your triple-clicking pleasure.) There is a patch to rc in there, so take a look at your /etc/rc and install the new one. If you have changed your /etc/rc, either cut & paste the relevant lines or take out the hunk pertaining rc and apply it to your /etc/rc. Then add the following to your kernel configuration file: pseudo-device ccd 4 (You can have as many of them as you want, or fewer than four, of course.) We recommend you to add "options DDB" too. This will make the kernel go into a debugger in case of a panic. That will make it easier for you to send us a complete bug report. (Note this will disable auto-rebooting after a panic, so don't do this on a machine that has to run unattended.) (6) How to use ccd Wait, you need to compile ccdconfig too! Go in there, do "make depend all install". If install complains about missing directories and such, make sure you have the correct Makefile.inc in the parent (/usr/src/sbin) directory. If you don't have one (like, you don't have the sbin source tree), just editing the ccdconfig Makefile and adding "BINDIR=/sbin" and "NOSHARED=YES" by hand should do. Also, you will need to create the device files. There is a patch to MAKEDEV included in ccd.patch, so go into etc/etc.i386 and install the new MAKEDEV into /dev. Then you can, say, "cd /dev; sh MAKEDEV ccd0" to create the appropriate device files for your first ccd devices, etc. Now, go and read the man pages. ccdconfig.8 should be installed by now; ccd.4 is still sitting in the source directory so go read it there. (Try "nroff -man ccd.4 | less -s".) Assuming you've read them, here is an example, if you have four partitions (sd1g, sd2g, sd3g, sd4g) you want to combine into one: echo "ccd0 16 none /dev/sd1g /dev/sd2g /dev/sd3g /dev/sd4g" > /etc/ccd.conf ccdconfig -Cv (to configure; you'll see a message here) disklabel ccd0 (just to make sure there is a valid disklabel) newfs /dev/rccd0c mount /dev/ccd0c /mnt (play with /mnt) umount /mnt ccdconfig -U (to unconfigure) (7) What's the second field in /etc/ccd.conf? That's the "interleave size". Basically, the ccd driver will write this many sectors (usually 512 bytes) to one disk before it moves to the next disk. As a special case, a zero here means no interleave, i.e., to concatenate disks serially. We have found that in FFS, a value of 16 usually optimizes read performance, while the write peaks with a much larger value (like 512). This probably has to do with cluster_write() thinking it's writing to a single disk when it's actually not. This is one of the things we are planning to fix. (8) Are there any caveats? Oh sure. One of them is "don't use a partition that starts at a beginning of the slice". So please leave some space at the beginning of the slice in the partitions you are combining (sd[1-4]g in the above example). Of course, if someone can figure out why and fix it, that will be great. Another is that if you specify odd numbers of disks for mirroring, it will say it's not going to use the last disk, but doesn't release the disk properly so you won't be able to use it elsewhere. We'll fix this soon. (9) My disk is totally hosed. It's all your fault! See (2). (10) Anything I can help? Well, any bug fix is welcome. In addition to the stuff mentioned above, we are aware of at least the following: a. The disklabel support is still old (pre-2.x FreeBSD style). We should be including instead of in ccd.c. Can someone take a look at this? b. On a similar note, if I do "disklabel -e ccdX" immediately after configuring the disk, it won't let me write it with the error: disklabel: ioctl DIOCWDINFO: No disk label on disk; use "disklabel -r" to install initial label It works if I do a "disklabel -w -r ccdX " first and then edit that label. I don't know if fixing the above will take care of this too. c. I'm not exactly sure what the "geometry" of this pseudo-disk means. If it doesn't matter, it's ok; if newfs (for instance) cares, we should give it a better set of default values. d. Someone please tell me how to create an lkm out of this. (11) Where should I send bug reports/fixes? Please send them to ccd@stampede.cs.berkeley.edu. This will reach the two primary developers (Satoshi and Nisha), as well as other interested parties. If you want to be added to this list, please send mail to Satoshi (asami@cs.berkeley.edu). (12) Where do I get new versions? They will be made available as ftp://stampede.cs.berkeley.edu/pub/ccd/ccd-.tar.gz so check this site regularly. Also, you can browse at http://stampede/cs.berkeley.edu/ccd/ which contains the latest development news and links to various tarballs. (13) I'm tired Yeah, I'm tired too. Well go to sleep now then, and try it tomorrow! Good night! Satoshi