There is some information available on shape changes in RAID arrays but I'm a little nervous and would like confirmation:
Problem: I have 2 500GB drive as software raid 5 (mdadm). I would like to free one of the two drives since RAID-redundancy is for wimps... Can I just
mdadm --grow --array-size=1
followed by a
mdadm --grow --raid-disks 1?
This seems too simple. How would I specify which drive gets freed? Part of the reason for this maneuver is that I don't have additional space to run a backup.
Edit: As it is, this is a non-std RAID5 implementation (see comments by Dave M or gman). However, please don't chastise me for recklessness. I am simply interested in the least risky method of doing this drive removal. Let's assume I have taken care of the backup issue but I'm not going to use it to rebuild from backup.
$ sudo mdadm --detail --test /dev/md1 /dev/md1: Version : 00.90 Creation Time : Sat Sep 1 18:08:21 2007 Raid Level : raid5 Array Size : 488383936 (465.76 GiB 500.11 GB) Used Dev Size : 488383936 (465.76 GiB 500.11 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 1 Persistence : Superblock is persistent
Update Time : Mon Nov 28 11:32:13 2011 State : clean
Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0
Layout : left-symmetric Chunk Size : 64K UUID : XXX (local to host XXX) Events : 0.29336 Number Major Minor RaidDevice State 0 8 33 0 active sync /dev/sdc1 1 8 17 1 active sync /dev/sdb1