Red Hat Bugzilla – Bug 122598
Anaconda creates suboptimal RAID5 configurations
Last modified: 2007-11-30 17:10:42 EST
From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6b) Gecko/20040105 Description of problem: Anaconda/Disk Druid creates RAID-5's with algoritm = 0 (left-assymetric.) However, the recommended algorithm for general use is algorithm 2 (left-symmetric.) Unfortunately, there is no easy way to recover this after system installation, so this is a major flaw. Version-Release number of selected component (if applicable): FC2test3 CD ISOs How reproducible: Always Steps to Reproduce: 1. Create a RAID-5 with Disk Druid. 2. Look at /proc/mdstat. 3. Read the md documentation. Additional info:
anaconda has never set this explicitly and instead just goes with the defaults for the raid tools/kernel. At this point, it's too late to change for FC2 (it wouldn't get any testing at all), so targeting for FC3.
This is somewhat misleading. Please note that raidtools are considered obsolete. mdadm defaults to left-symmetric (2). Also note this applies to RAID-6 as well as RAID-5.
Switching to madadm for FC3, changes are in CVS (which will then follow the default of mdadm, I'm not going to change the defaults there either since the tool should dtrt by default)