I found this old message, it may help. ====================================== http://www.corpit.ru/mjt/mdctl.c - a very small utility similar to raidtools suite. I wrote this program to use it inside an initrd to bring raid arrays up at boot time - where the size of executable and simplicity is at premium. Differences between this implementation and raidtools are: - size. When compiled with dietlibc, executable is about 7kb on i386. - it does not have mkraid utility and other fun stuff. Supported are - raidstart - raidstop - raidhot{add,remove,generateerror) - raidsetfaulty i.e., only "simple" commands - just ioctls in fact. - it uses NO config file like all the raidtools suite. I.e., it is more like mdadm in this respect. All parameters are accepted in the command line. This makes the utility handy inside read-only boot-time environment (you may e.g. parse md=... kernel parameter and convert it into mdctl commandline) - `mdctl start' tries to bring an array using ALL components of the array given in the command line, until successeful (raidstart tries only first component, and if that is missing but other component(s) are available, operation will fail). Usage: mdctl start /dev/mdN /dev/hda1 /dev/hdb1 /dev/hdc1 equivalent to md=N,/dev/hda1,/dev/hdb1,/dev/hdc1 boot parameter, but you can't specify raid level (it will be read from the superblock), and kernel may choose to bring up another mdN (as indicated by super-minor) mdctl {stop,readonly,ro,readwrite,rw} /dev/mdN mdctl {add,remove,setfaulty,generaterror} /dev/mdN /dev/hda1 This tiny code released under GPL licence... in a hope it will be useful to someone else too, not only to me ;) Enjoy. /mjt - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html -----Original Message----- From: linux-raid-owner@vger.kernel.org [mailto:linux-raid-owner@vger.kernel.org] On Behalf Of Arkadiusz Miskiewicz Sent: Friday, January 16, 2004 6:47 PM To: linux-raid@vger.kernel.org Subject: Fwd: starting an array on Linux, advise needed I've asked Neil about that previously but he didn't respond, so I'm asking here.... ---------- Przekazana wiadomość ---------- Subject: starting an array on Linux, advise needed Date: pon 15. grudnia 2003 13:35 From: Arkadiusz Miskiewicz <arekm@pld-linux.org> To: neilb@cse.unsw.edu.au Hi, I need smallest possible version of tool for starting md array on Linux. Right now I'm doing: raid_start /dev/md0 /dev/hda1 /dev/hdb1 /dev/hdc1 and code does fd_md = open(argv[1], O_RDWR, 0); for (i = 2; i < argc; i++) { if (stat(argv[i], &st)) { bb_perror_msg("error stating raid builing device `%s'", argv[i]); continue; } if (ioctl(fd_md, START_ARRAY, (unsigned long) st.st_rdev) == -1) { bb_perror_msg("error starting raid device `%s:%s'", argv[1], argv[i]); continue; } return 0; } return 1; so it starts using first working device and tries to assemble array from other devices found in superblock. Unfortunately there are some hard disk controllers which on 2.4 provide /dev/hdX devices while on 2.6 these are visible as /dev/sdX so even raid_start /dev/md0 /dev/sda1 /dev/sdb1 /dev/sdc1 won't work because it will try to use /dev/sda1 and hdb1+hdc1 (from superblock). How simplest possible version should look like - is this below ok? fd_md = open(argv[1], O_RDWR, 0); ioctl(fd_md, SET_ARRAY_INFO, NULL); for (i = 2; i < argc; i++) { stat(argv[i], &disk); ioctl(fd_md, ADD_NEW_DISK, &disk); } ioctl(fd_md, RUN_ARRAY, NULL); and what if some of these ioctls fails - would be safe to do ioctl(fd_md, STOP_ARRAY, NULL)? Thanks for help. -- Arkadiusz Miśkiewicz CS at FoE, Wroclaw University of Technology arekm.pld-linux.org AM2-6BONE, 1024/3DB19BBD, arekm(at)ircnet, PLD/Linux ------------------------------------------------------- The other problem is that after switching from 2.4.21 to 2.6.1 I got: FS: Mounted root (romfs filesystem) readonly. + insmod /lib/modumd: md driver 0.90.0 MAX_MD_DEVS=256, MD_SB_DISKS=27 les/2.6.1-1.csetraid5: measuring checksumming speed 20040116_0629smp 8regs : 916.000 MB/sec /kernel/drivers/ 8regs_prefetch: 732.000 MB/sec md/md.ko Using 32regs : 408.000 MB/sec /lib/modules/2.6 32regs_prefetch: 400.000 MB/sec .1-1.cset2004011 pIII_sse : 996.000 MB/sec 6_0629smp/kernel pII_mmx : 1252.000 MB/sec /drivers/md/md.k p5_mmx : 1308.000 MB/sec o + insmod /libraid5: using function: pIII_sse (996.000 MB/sec) /modules/2.6.1-1md: raid5 personality registered as nr 4 .cset20040116_06SCSI subsystem initialized 29smp/kernel/drivers/md/xor.ko Using /lib/modules/2.6.1-1.cset20040116_0629smp/kernel/drivers/md/xor.ko + insmod /lib/modules/2.6.1-1.cset20040116_0629smp/kernel/drivers/md/raid5.ko Using /lib/modules/2.6.1-1.cset20040116_0629smp/kernel/drivers/md/raid5.ko + insmod /lib/modules/2.6.1-1.cset20040116_0629smp/kernel/drivers/scsi/scsi_mod.ko Using /lib/modules/2.6.1-1.cset20040116_0629smp/kernel/drivers/scsi/scsi_mod.ko + insmod /lib/modules/2.6.1-1.cset20040116_0629smp/kernel/drivers/scsi/sd_mod.ko Using /lib/modules/2.6.1-1.cset20040116_0629smp/kernel/drivers/scsi/sd_mod.ko + insmod /lib/modules/2.6.1-1.cset20040116_0629smp/kernel/fs/jbd/jbd.ko Using /lib/modules/2.6.1-1.cset20040116_0629smp/kernel/fs/jbd/jbd.ko + insmod /lib/modules/2.6.1-1.cset20040116_0629smp/kernel/fs/mbcache.kmd: could not lock unknown-block(8,34). o Using /lib/momd: could not import unknown-block(8,34)! dules/2.6.1-1.csmd: autostart unknown-block(0,2082) failed! et20040116_0629smd: could not lock unknown-block(8,18). mp/kernel/fs/mbcmd: could not import unknown-block(8,18)! ache.ko + insmomd: autostart unknown-block(0,2066) failed! d /lib/modules/2md: could not lock unknown-block(8,2). .6.1-1.cset20040md: could not import unknown-block(8,2)! 116_0629smp/kernmd: autostart unknown-block(0,2050) failed! el/fs/ext3/ext3.ko Using /lib/modules/2.6.1-1.cset20040116_0629smp/kernel/fs/ext3/ext3.ko + raid_start /dev/md0 /dev/sdc2 /dev/sdb2 /dev/sda2 raid_start: error starting raid device `/dev/md0:/dev/sdc2': Invalid argument raid_start: error starting raid device `/dev/md0:/dev/sdb2': Invalid argument raid_start: error starting raid device `/dev/md0:/dev/sda2': Invalid argument romfs: unable to read superblock EXT3-fs: unable to read superblock Kernel panic: VFS: Unable to mount root fs on md0 (kernel messages are unfortunately mixed with messages from userspace apps) -- Arkadiusz Miśkiewicz CS at FoE, Wroclaw University of Technology arekm.pld-linux.org AM2-6BONE, 1024/3DB19BBD, arekm(at)ircnet, PLD/Linux - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
