Changes Prior to 2.6.1 release - --monitor was producing some meaningless warnings due to a bug. - Fix some compiler warnings. - Fully support --grow for raid6. If a reshape crashed during the critical period, mdadm wouldn't restore the Q information properly. - Update documentation for --grow. Changes Prior to 2.6 release - Fixed UUID printing in "--detail --brief" for version1 metadata. - --update=resync did exactly the wrong thing for version1 metadata. It caused a resync to not happen, rather than to happen. - Allow --assemble --force to mark a raid6 clean when it has two missing devices (which is needed else if won't assemble. Without this fix it would only assemble if one or zero missing devices. - Support --update=devicesize for cases where the underlying device can change size. - Default to --auto=yes so the array devices with 'standard' names get created automatically, as this is almost always what is wanted. - Give useful message if raid4/5/6 cannot be started because it is not clean and is also degraded. - Increase raid456 stripe cache size if needed to --grow the array. The setting used unfortunately requires intimate knowledge of the kernel, and it not reset when the reshape finishes. - Change 'Device Size' to 'Used Dev Size' because it only shows how much of each device is actually used, not how big they are. - --wait or -W will wait for resync activity to finish on the given devices. - Fix some problems with --update=uuid and add a test. - If two drives in a raid5 disappear at the same time, then "-Af" will add them both in rather than just one and forcing the array to 'clean'. This is slightly safer in some cases. - Check device is large enough before hot-add: this improves quality of error message. - Don't hold md device open for so long in --monitor mode - map_dev can be slow and interferes with trying to stop the array. - Support --uuid= with --create to choose your own UUID. - New major more "--incremental" for incremental assemble of arrays, intended for use with udev. Changes Prior to 2.5.6 release - Fix bug which meant "bitmap=xxx" in mdadm.conf was not handled properly. - Documentation updates. - Fix bug that caused infinite loop when doing auto-assembly, in certain cases where arrays couldn't be assembled. Changes Prior to 2.5.5 release - Don't #include linux/blkpg.h as that isn't safe. Just include the content literally. - Reduce maximum bitmap usage when working with bitmap files, so that a only single-page allocations are made, even on 64bit hosts with 4K pages. - Close stray fd in mdassemble so that it can assemble stacked devices - If mdassemble finds an array already assembled, it marks it read-write. - Remove error in md_open if array is already active. This isn't needed and gets in the ways if an array was created e.g. in initramfs, but device doesn't yet exist in /dev. - When --assemble --scan is run, if all arrays that could be found have already been started, don't report an error. - Fix a couple of bugs related to raid10 and the new 'offset' layout. - Improve error message when a wrong '--update' option is given. Changes Prior to 2.5.4 release - When creating devices in /dev/md/ create matching symlinks from /dev. e.g. /dev/md0 -> /dev/md/0. Allow this to be disabled in mdadm.conf or on command line. - Fix some endian-ness issues with version-1 superblocks (affects bigendian only). - Fix endian problem with 'bitmap' metadata - Allow a number (of partitions) after the 'yes' option to --auto= This is particularly useful in the 'create' line in mdadm.conf. - Remove partitions from any whole device that is made part of an md array. This is a work-around for annoying messages when the first block on some drive accidentally looks like a partition table. Changes Prior to 2.5.3 release - Document v0.91 superblocks in md.4 - Make GPL explicit in man pages. - Fix recent breakage of starting degraded arrays. - Tidyup automatic name choice for v-1 arrays: /dev/md_d0 now becomes '0', not '_d0'. Changes Prior to 2.5.2 release - Fix problem with compiling with gcc-2 compilers - Fix compile problem of post-incrmenting a variable in a macro arg. - Stop map_dev from returning [0:0], as that breaks things. - Add 'Array Slot' line to --examine for version-1 superblocks to make it a bit easier to see what is happening. - Work around bug in --add handling for version-1 superblocks in 2.6.17 (and prior). - Make -assemble a bit more resilient to finding strange information in superblocks. - Don't claim newly added spares are InSync!! (don't know why that code was ever in there) - Work better when no 'ftw' is available, and check to see if current uclibc provides ftw. - Never use /etc/mdadm.conf if --config file is given (previously some code used one, some used the other). Changes Prior to 2.5.1 release - Various fixes for gcc warnings - uclibc warnings - Makefile improvements for static linking/intalling - Makefile uninstall target - Really fix return status of --examine - Typos - Byteorder stuff (again) - Don't try to create devices with --manage or --grow - allow default metadata (superblock) type to be specified in mdadm.conf - Get --stop to list devices stopped but honour --quiet - remove libssl dependency - Avoid some misdetection of overlapping partitions - Fix memory leak in --monitor mode Changes Prior to 2.5 release - Support 'mailfrom' line in mdadm.conf so the From: line in alert emails can be explicitly set. - Arrange that SparesMissing (which is similar in import to DegradedArray) generates an Email. - Assume "DEVICE partitions" if no DEVICE line is given. - Support new 'offset' layout for raid10. - When creating a bitmap file, choose a chunksize to limit number of bitmap chunks to 2 million. More than this can cause kmalloc failure. - New 'CREATE' line in mdadm.conf for defaults such as owner, group, mode and auto-flag - --detail checks if array has been started or not and includes that in report. - When using --update=uuid on an array with a bitmap, update the bitmap's uuid too. - Add a copy of /proc/mdstat to the mail message sent by mdadm --monitor. - New flag --no-degraded to avoid starting arrays if there are fewer devices available than last time the array was started. This is only needed with --scan, as with --scan, that behaviour is the default. - Support for 'homehost' concept. This is a fairly major update. It includes a configfile option and a command line option for specifying a homehost, records that host in the superblock, and reports the homehost where possible. - Support for Auto Assembly. "mdadm -As" will, if provided with the name of a homehost, try to assemble all arrays it can find that were created for that homehost. See man pages for more details. Changes Prior to 2.4.1 release - Honour --write-mostly when adding to an array without persistent superblocks. - Fix alignment problem in version-1 superblocks. NOTE: This is an incompatable change affecting raid5 reshape. If you want to reshape a raid5 using version-1 superblocks, use 2.6.17-rc2 or later, and mdadm-2.4.1 or later. Changes Prior to 2.4 release - Rewrite 'reshape' support including performing a backup of the critical region for a raid5 growth, and restoring that backup after a crash. - Put a 'canary' at each end of the backup so a corruption can be more easily detected. - Remove useless 'ident' arguement from ->getinfo_super method. - Support --backup-file for backing-up critical section during growth. - Erase old superblocks (of different versions) when creating new array. - Allow --monitor to work with arrays with >28 devices - Report reshape information in --detail - Handle symlinks in /dev better - Fix mess in --detail output which a device is missing. - Manpage tidyup - Support 'bitmap=' in mdadm.conf for auto-assembling arrays with write-intent bitmaps in separate files. - Updates to md.4 man page including section on RESTRIPING and SYSFS Changes Prior to 2.3.1 release - Fixed -O2 compile so I could make and RPM. - Type cast number to be printed %llu so it compiles on 64bit machines. (Thanks Luca). - Stop using asm/byteorder.h - to make Redhat happy :-( - Require bitmap files to have a '/' in their name. - Error-check a few syscalls - code from SuSE package. Changes Prior to 2.3 release - Try /etc/mdadm/mdadm.conf if /etc/mdadm.conf doesn't exist. This provided compatability for Debian. - Fixed for version-1 superblock: report chunksize for raid6 and raid10 make sure device size used is a multiple of chunksize - Fix "--assemble --scan" crash. - Fix completely failure to create array on ppc64 - Fix memcmp in place of memcpy - A few minor improvements to online help - Clean up usage of 'long long' for used-size of devices, so that it is possible to create a raid1 of 7TB devices! - Make internal bitmaps work on 7TB raid1 arrays. - Provide error message if --examine doesn't find any superblock. - Report 'reshape' status in --examine - this depends on kernel patches that are not yet finalised. - Report bitmap status in --detail and --examine - Default to v1 superblocks instead of v0.90 if the array is too big for 0.90 to handle. - Sort the output of "mdadm --detail --scan" so that it is in a suitable order for assembling arrays. i.e. components come before an array that they are part of. - Print size of large reiserfs array properly went warning of possible confilcts. Changes Prior to 2.2 release - Assorted bug fixes - Support write-intent-bitmaps on raid10 - Support little-endian (Rather than hostendian) bitmaps. - Return correct error code from 'mdadm -S' - Remove extra blank line from 'mdadm -Eb' output. - Improve option parsing so that -a and -b do not have optional arguements: the arg is either required or not depending on context. - Allow scanning of devices listed in /proc/partitions even if they don't appear in /dev. - Support --assume-clean in --create mode as well as --build - Add support for --monitor to report to syslog: -y or --syslog. Thanks to Ross Vandegrift - --monitor now reports which device failed in a 'Fail' message This broke with 2.6 - Improve chance of array starting properly after a crash. mdadm was insisting the event numbers were identical, but this isn't needed, and is a problem if the crash was while the metadata was being updated. - Support --update==uuid - Added README.initramfs and mkinitramfs to help people use an initram for starting md arrays at boot. Changes Prior to 2.1 release - Fix assembling of raid10 array when devices are missing. mdadm now correctly detects if a array is workable or not depending on which devices are present, and so will correctly handle "--assemble --force" if multiple devices have failed. - Report raid10 layout in --examine output. - Fix assembling of arrays that use the version-1 superblock and have spares. Previously the spares would be ignored. - Fix bug so that multiple drives can be re-added at once. - Fix problem with hot-adding a bitmap to version-1-superblock arrays. Changes Prior to 2.0 - Support assembling from byte-swapped superblocks metadata type "0.swap" and --update=byteorder - write-mostly and write-behind support for raid1. - Support --name= and 'name=' config entry for identifying arrays be name. - RAID10 in man pages. - Lot of minor manpage updates Changes Prior to 2.0-devel-3 release - Assorted fixes for multiple bugs... - Add test suite Changes Prior to 1.12.0 release Several of these are backported from the Debian package - Don't use 'lstat' to check for blockdevices, use stat. - Document --size=max option for --grow - Document SparesMissing event and DeviceDisappeared/WrongLevel - --stop --scan repeatly cycles until no more progress can be made so that stack devices are stopped properly - Minor type rationalisation for ident->uuid - now always 'int[]' - Fix type in online help for --grow (was -F, now -G) - Allow --auto command line option to set default auto= value when running "--assemble --scan". Previously --auto was ignored if --scan was given - Fix a few type casts - Fix parsing of /dev/md/N in is_standard - Fix rounding errors in human_size() - Fix silly example in mdadm.conf-examples - When finding a /dev name for a device, prefer shorter names - Suppress listing of devices= in --brief output of -D or -E, unless -v is given (-vv gives the old behaviour with -Dsv). This is because the device list can change and so is not a stable aspect of the array - Allow --force with --grow so '-Gfn1' works (on raid1) - Replace sprintf calls with snprintf (to quiet diet-libc) - Add man page for mdassemble - Fix compilation with tinyc Changes Prior to 1.11.0 release - Fix embarassing bug which causes --add to always fail. Changes Prior to 1.10.0 release - Fix bug with --config=partitions - Open sub-devices with O_EXCL to detect if already in use - Make sure superblock updates are flushed directly to disk. Changes Prior to 2.0-devel-1 release - Support for version-1 superblock. See --metadata option. - Support for bitmap based intent logging. - Minor fixes. Changes Prior to 1.9.0 release - Fix rpm build problem (stray %) - Minor manpage updates - Change "dirty" status to "active" as it was confusing people. - --assemble --auto recognises 'standard' name and insists on using the appropriate major/minor number for them. - Remove underscore from partition names, so partitions of "foo" are "foo1", "foo2" etc (unchanged) and partitions of "f00" are "f00p1", "f00p2" etc rather than "f00_p1"... - Use "major", "minor", "makedev" macros instead of "MAJOR", "MINOR", "MKDEV" so that large device numbers work on 2.6 (providing you have glibc 2.3.3 or later). - Add some missing closes of open file descriptors. - Reread /proc/partition for every array assembled when using it to find devices, rather than only once. - Make "mdadm -Ss" stop stacked devices properly, by reversing the order in which arrays are stopped. - Improve some error messages. - Allow device name to appear before first option, so e.g. mdadm /dev/md0 -A /dev/sd[ab] works. - Assume '-Q' if just a device is given, rather than being silent. - Change "dirty" status to "active" as it was confusing people. Changes Prior to 1.8.0 release - Makefile cleanup from Luca Berra - --pid-file (-i) to set a pid file to use with --monitor --daemonise - Fix typo in mdadm man page - Fix coredump when "-s" used with no config file present. - Support new "faulty" personality which can inject synthetic faults. (Not in kernel.org yet at 1Nov2004) - Support raid0/linear on devices > 2 Terabytes - Make sure raid6 resyncs when created with one missing device Changes Prior to 1.7.0 release - Support "--grow --add" to add a device to a linear array, if the kernel supports it. Not documented yet. - Restore support for uclibc which was broken recently. - Several improvements to the output of --detail, including reporting "resyncing" or "recovering" in the state. - Close filedescriptor at end of --detail (exit would have closed it anyway, so this isn't abig deal). - Report "Sync checkpoint" in --examine output if appropriate. - Add --update=resync for --assemble mode to for a resync when the array is assembled. - Add support for "raid10", which is under development in 2.6. Not documented yet. - --monitor now reads spare-group and spares info from config file even when names of arrays to scan are given on the command line Changes Prior to 1.6.0 release - Device name given in -Eb is determined by examining /dev rather than assuming /dev/md%d - Fix bug in --monitor where an array could be held open an so could not be stopped without killing mdadm. - Add --grow mode. Currently only --size and --raid-disks can be changed. Both require kernel support which, at the time of writing, is not in a release kernel yet. - Don't print out "errors" or "no-errors" in -D and -E, as the bit is never set or used. - Use md event notification in 2.6.??? to make --monitor mode respond instantly to events. - Add --auto= option and auto= configfile entry to tell mdadm to create device files as needed. This is particularly useful with partitioned arrays where the major device number can change. - When generating --brief listing, if the standard name doesn't exist, search /dev for one rather than using a temp name. - Allow --build to build raid1 and multipath arrays. - Add "--assume-clean" for Create and Build, particularly for raid1 Note: this is dangerous. Only use it if you are certain. - Fix bug so that Rebuild status monitoring works again. - Add "degraded" and "recovering" options to the "Status:" entry for --detail Changes Prior to 1.5.0 release - new commands "mdassemble" which is a stripped-down equivalent of "mdadm -As", that can be compiled with dietlibc. Thanks to Luca Berra . It can be using in an initramfs or initrd. - Fix compiling error with BLKGETSIZE64 and some signed/unsigned comparison warnings. - Add Rebuild Status (% complete) to --detail output. - Support "--monitor --test" which will generate a test alert for each array once, to test notification paths. - Generate RebuildFinished event when rebuild finishes. - Support for raid6 as found in 2.6.2 - thanks to H. Peter Anvin - Support partitioned md arrays with a different major number and naming scheme (md_dX in /proc/mdstat, /dev/md/dXpY in /dev). Changes Prior to 1.4.0 release - Document fact that creating a raid5 array really creates a degraded array with a spare. - Add "spares=" tag to config file and generate it wit --detail and --examine - Add "SparesMissing" event when --monitor first sees an array and it doesn't have the enough spare devices. - Add --update=summaries for --assemble to update summary information in superblock, and correct other inconsistancies in the superblock. - Add --test option to --detail to set a meaningful exit status. Changes Prior to 1.3.0 release - Make 'size' and unsigned long in Create to allow creation of larger arrays. - Explicitly flag spare devices as 'spare' in --detail and --examine output. Previously they simply had no flags lists. - Make MailCmd (for monitor) configurable in Makefile, and default to "/usr/sbin/sendmail -t". Also split out the warning related flags into CWFLAGS for easier build configurability. - Minor bugfix in Manage code. - --monitor now notices and reports degraded arrays at startup using "DegradedArray" event, and also has a --oneshot option to only report DegradedArrays, and then exit. - Small man-page clarification w.r.t. raid levels and raid4 in particular. - Disallow creation of arrays with only one device as this is probably a mistake. --force will override this check. - Correct some misleading documentation in the "mdadm --create --help" message. - Ignore chunksize if raid1 or multipath. - Explicit statement in man page that raid-disks cannot be changed after array is created. - Improve message when attempting to start an array with insufficient devices. Instead of required the array to be full, we only require it has as many active devices as last time. Changes Prior to 1.2.0 release - Fix bug where --daemonise required an argument. - In --assemble --verbose, print appropriate message if device is not in devices= list - Updated mdadm.conf.5 to reflect fact that device= takes wildcards - Typos: componenet -> component - Reduce size of "--help" message put excess into "--help-options" - Fix bug introduced when MD_SB_DISKS dependancy removed, and which caused spares not be assembled properly. - Print appropriate message if --monitor --scan decides not to monitor anything. Changes Prior to 1.1.0 release - add --deamonise flag for --monitor - forks and prints pid to stdout - Fix bug so we REALLY clear dirty flag with -Af - -Db now prints a 'devices=' word for each array. - "mdadm -A /dev/md0" will get info from configfile, even without scan - When assembling multipath arrays, ignore devices which are flagged as having errors. - take --super-minor=dev to mean "use the minor number of the mddev being assembled. - take --config=none to mean "completely ignore config file" - Make --monitor require --scan or a device list. Changes Prior to 1.0.9 release - Documentation updates including kernel parameters documented in md.4 - --assemble --force for raid4/5 will mark clean, needed for 2.5 - --detail prints out the events counter as well - flush device before reading superblock to be sure to get current data - added mdadm.static target to makefile for static linking - --monitor was ignoring /dev/md0 due to off-by-one error - Fix assorted typos - Fix printing of Gibibytes - calc was wrong. - Fix printing of Array Size in --detail when very big. - --monitor no longer tries to work for raid0 or linear as these have nothing to be monitored. - The word 'partitions' on a DEVICE line will cause all partitions listed in /proc/partitions to be considered - If the config file is called 'partitions' then it will be treated as though it contained exactly 'device partitions' so e.g. mdadm -Ebsc partitions will find all raid partitions easily. - successfully assemble multipath devices by ignoring raid_disk value from superblock (it is always the same). - --assemble not tied to MD_SB_DISKS limit quite so much - Support compiling with tcc - Support compiling with uclibc - just skip scan of /dev - Add --update= option for Assemble mode. Either sparc2.2 or super-minor updates are possible. See mdadm.8 Changes Prior to 1.0.1 release - Round off MB/GiB etc values instead of round down. - Add --sparc2.2 option to examine to shift superblock around and --sparc2.2update to rewrite the superblock - Fix assorted typos in online help Changes Prior to 1.0.0 release - Allow --config with Misc mode (for --examine --scan) - Add $(CXFLAGS) to end of CFLAGS in makefile - When making an N disk raid5 array, the Nth drive is moved to the end of the array as a spare rather than being shifted up one place. This means that when the kernel builds onto the last spare and inserts it, the devices will be in the expected order. - Man page improvements Changes Prior to 0.8.2 release - Correct spelling of persist[ae]nce/persist[ae]nt. - Change "disk" to "device" in options and config file - convert array size to "long long" *before* shift-left in -D and -Q Changes Prior to 0.8.1 release - Add "INSTALL" file. - Fix some "i" variables that were not being set properly - Initialise minsize and maxsize so that compilers don't complain. - Tidy up Makefile and mdadm.spec installations - Add "multipath" to documentation of valid levels Changes Prior to 0.8 release - Fix another bug in Assemble.c due to confusing 'i' with 'j' - Minimal, untested, support for multipath - re-write of argument parsing to have more coherent modes, - add --query,-Q option - Update mdadm.8 to reflect arg processing change and --query - Change "long" to "unsigned long" for device sizes - Handle "mailaddr" and "program" lines in config file for follow/scan mode. - --follow --scan will exit if no program or mail found - Add MAILADDR and PROGRAM to mdadm.conf-example - Spell check man pages - consistently use "component devices" instead of "subdevices" - Make -Wall -Werror really work and fix lots of errors. - --detail and --stop can have --scan which chooses devices from /proc/mdstat - --monitor detects 20% changes in resync, failed spares, disappearing arrays, - --monitor --scan will automatically add any devices found in /proc/mdstat - --monitor will move spares between arrays with same spare-group if necessary - Documentation for Monitor Mode - --query notes if the array containing the given device is active or not - Finished md.4 man page. Changes Prior to 0.7.2 release - mdadm.spec updates and ifdef BLKGETSIZE64 from Luca Berra -- bluca@comedia.it - more mdadm.spec updates from Gregory Leblanc - make directory for mdadm.conf configurable in Makefile - Finished mdadm.conf.5. Removed details of conf file from mdadm.8 leaving a reference to mdadm.conf.5. - Fix bug in Assemble.c, thanks to Junaid Rizvi - Get --assemble --force to make sure old major/minor numbers are consistant, as md.c worries about this :-( Changes Prior to 0.7.1 release - update mdadm.spec - use BLKGETSIZE64 if available for array size - give human readable as GiB/MiB and GB and MB, with 2 decimal point precision - Only warn about size variation for raid1/4/5. - Started md.4 man page - Started mdadm.conf.5 man page Changes Prior to 0.7 release - Fix makefile to install binary at /sbin and not /sbin/sbin Also install man page. - Add --zero-superblock based on --destroywithextremeprejudice from Dale Stephenson - change name to mdadm. It is palandromic, and much nicer to pronouce. Changes Prior to 0.6 release - Remove the limit on the number of device names that can be given on the command line. - Fix bug in --assemble --force where it would only update a single superblock. - Fix bogus printing of big numbers not being block devices when given names of devices that don't exist. - When --assemble --force, consider superblocks with an event count that is 1 behind as out-of-date. Normally they are considered up-to-date (as the kernel assumes this too). - When marking drives as not-failed in the superblock, we also mark them as ACTIVE and SYNC. - Don't start arrays for which not all drives are available unless: --scan which implies that all drives were found automatically --run which means the user knows what they want --force which means that we are fixing something broken - Make sure all device numbers passed as 3rd arg of ioctl are passed as unsigned lock, so that it works on SPARC - If HOT_ADD_DISK failes for -a, then only try ADD_NEW_DISK if we cannot read from the array, i.e. if the array is not started yet. - man page update - Taught Examine to handle --scan. It examines all devices listed on DEVICE lines in the config file. - Added --brief (-b) flag for Examine and Detail to print out and mdctl.conf compatible description with uuid=, level=, disks= and - for Examine - devices= --examine --brief collects all devices the make the one array and list them as one entry. - Added level= and disks= options to ARRAY lines in config files so --brief output could be used as-is. - Make parity style ({left,right}-{,a}symmetric) consistantly use -, never _. - Add "Array Size" to --detail output - Change "Size" to "Device Size" and exclude from Detail of arrays that do not have a consistent device size. - Add Human readable MiB or GiB value on size lines of Detail and Examine - --assemble --scan doesn't complain about active drives - require number of spares given in -x to be listed. - Made --build actually work. Changes Prior to 0.5 release --assemble: spare drives are handled properly. --force can be used to recover from 2-drive failures on RAID5 If you belive that /dev/hda1 /dev/hdb1 /dev/hdc1 /dev/hdd1 should make a raid5 array, but it has experienced multiple failures and wont start, then mdctl --assemble --force /dev/md0 /dev/hd[abcd]1 Should update the superblock on the newest failed drive and restart the array in degraded mode. You should then remove the remaining failed drive and re-add it (if you are happy that it might work). Ofcourse whenever you have a 2-drive failure, you have a risk of corruption in data that hasn't be changed for a long time. So this doesn't give you your array back all nice and happy, but it does allow you to recover data that might not be corrupt. More flexibility in identifying a RAID array in the mdctl.conf e.g. array /dev/md4 super-minor=4 assembles /dev/md4 from all devices found that have a raid superblock that says the minor number of the array is 4. If the blocks with the right minor number do not all have the same UUID, an error is flags and no assembly happens. array /dev/md3 devices=/dev/hd[abc]2 Assembles /dev/md3 drom /dev/hda2 /dev/hdb2 and/dev/hdc2. All devices must exist and have raid superblock with the same uuid. If two identity specifiers are used, only devices that match all of them are considered, so array /dev/md2 devices=/dev/hd?2 super-minor=2 will assemble /dev/md2 using all /dev/hd?2 devices which have a raid superblock with minor number 2. --create: When listing devices for --create, the word "missing" can be used to indicate that the respective slot does not have a working drive currently. This is similar to the "failed-disk" directive in mkraid/raidtab. e.g. mdctl --create --level=5 -raid-disks=4 --spare-disks=2 /dev/md0 /dev/sda /dev/sdb missing /dev/sdc /dev/sdd /dev/sde will create a raid5 array with the third slot empty, and two spares. By default, raid5 arrays are created with the last slot empty and drive listed for the last slot added as a spare. If a "missing" slot is given, or if --force is given, then --create does exactly what you ask and doesn't try to be clever. --follow / --monitor: This is a new mode. I couldn't stop my self from picking a name starting with F (as current modes start A,B,C,D,E) but I relented and provided an alternate name that is somewhat more meaningful. In this mode, mdctl does not exit, but runs continuously and periodically polls all the md devices to see if they have had any interested state change. The changes that it currently notices are: Fail - an active disc fails FailSpare - a spare, that was presumably being build, fails ActiveSpare - a spare becomes active, presumably after a rebuild. Options: --mail mailaddress - send Email on any Fail* event --program program - run the program on any event. Args are: eventname mddevice subdevice(if-known) --delay seconds - change from the default 60second pause between polls. I plan to add functionality to this mode to allow sharing of spare drives. If an array is marks "spare-group=fred", and it has a failed drive and no spares, and if some other array is also "spare-group=fred" and it has no failed drives, but does have a spare drive that is big enough, the spare will be moved to the first array. I also have the idea of adding a --grow mode which will re-organise the data on an N disk raid0/4/5 array to be on an N+M disk array. I have no concrete plans for this though. I got rid of the "v" in the archive file name, and include the version number in the directory created by the archive. There is now a man page and mdctl.spec (for rpm) thanks to Danilo Godec . Ofcourse, the man page is now out of date and despite being based on the --help output, is not wholy correct. After I get --follow working properly, I plan to revise the various documentation and/or the code to make sure the two match.