Managing RAID on Linux

Name

raidreconf

Synopsis

raidreconf [options] -m mddevice

raidreconf can reconfigure certain properties of a RAID-0 or RAID-5 without data loss.

First, it can be used to resize an existing array. Normally, if you wanted to add or remove a disk from an array, you would need to back up your data, create a new array, and then restore the data. raidreconf circumvents the backup and restore steps by inserting or removing a device and reorganizing the data so that it spans the remaining disks.

raidreconf can also be used to import or export data to or from an array. That means you can take a single block device and use raidreconf to transfer data block-by-block onto an already existing software RAID. You can also export data from an existing array onto a single block device, provided the target device has enough space. raidreconf can also convert between RAID-0 and RAID-5. Finally, raidreconf can alter the chunk-size of an array.

raidreconf does not support linear mode, RAID-1, or RAID-4 and should never be used with these RAID levels.

raidreconf was originally written by Jakob OEstergaard (he is also its current maintainer), but some critical bug fixes were implemented by Danny Cox. raidreconf is included with raidtools-1.0 and is also available from http://unthought.net/raidreconf/.

Be advised that raidreconf is still very much beta software, even though it looks like it could be widely distributed with raidtools in the near future. I strongly recommend checking its web site and version history ...