Hi, Sorry if this subject is already done to death on the group but I have read the archives through google and couldn't find anything similar. Also apologies for the rather long winded post, just be thankful I didn't include all the straces... ;-P I have an easily repeatable problem with software raid and kernel 2.4.18/19 + raidtools2 under debian. The root device (/dev/md0) has /dev/hda1 and /dev/hdc1. Here is a chunk of the lilo.conf: [----- lilo.conf -----] # Specifies the boot device. This is where Lilo installs its boot # block. It can be either a partition, or the raw device, in which # case it installs in the MBR, and will overwrite the current MBR. # boot=/dev/hda # Specifies the device that should be mounted as root. (`/') # root=/dev/hda1 [---------------------] You cannot do the following: raidhotadd /dev/md0 /dev/hda1 as it returns this: /dev/md0: can not hot-add disk: invalid argument. an strace indicates: open("/dev/md0", O_RDWR) = 4 fstat64(4, {st_mode=S_IFBLK|0660, st_rdev=makedev(9, 0), ...}) = 0 stat64("/dev/hda1", {st_mode=S_IFBLK|0660, st_rdev=makedev(3, 1), ...}) = 0 ioctl(4, 0x928, 0x301) = -1 EINVAL (Invalid argument) write(2, "/dev/md0: can not hot-add disk: ", 32/dev/md0: can not hot-add disk: ) = 32 write(2, "invalid argument.\n", 18invalid argument. ) = 18 exit_group(1) = ? the ioctl call should succeed. Similar things occur with other raid management tools, e.g. lsraid -A -a /dev/md0: [dev 9, 0] /dev/md0 BC38988B.7A6BC5D2.5084B74A.88CE39EF online [dev ?, ?] (unknown) 00000000.00000000.00000000.00000000 missing [dev 22, 1] /dev/hdc1 BC38988B.7A6BC5D2.5084B74A.88CE39EF good and strace indicates that it isn't even attempting to acknowledge the existence of /dev/hda1!! Which is valid, correctly partitioned and should be in the raid. Attempting other operations on the disk shows that inodes are held open. Can anyone elighten me? It appears to affect whatever root= device is specified, however I thought i'd change it to /dev/hdc1 and boot but the machine died and I had to use grub. So in summary: 1) am I being stupid? 2) is something wrong? 3) is this perhaps normal behaviour? Thanks, any replies gratefully received at this point in time as I have another 3 machines to set up in a similar fashion. Paul - 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