Bug 844492 - LVM RAID: Support 2-way mirror RAID10
LVM RAID: Support 2-way mirror RAID10
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: lvm2 (Show other bugs)
Unspecified Unspecified
high Severity low
: rc
: ---
Assigned To: Jonathan Earl Brassow
Cluster QE
Depends On: 886658 889358
Blocks: 857209
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Reported: 2012-07-30 18:10 EDT by Jonathan Earl Brassow
Modified: 2013-02-21 03:13 EST (History)
12 users (show)

See Also:
Fixed In Version: lvm2-2.02.98-1.el6
Doc Type: Release Note
Doc Text:
LVM Support for 2-way Mirror RAID10 LVM is now capable of creating, removing, and resizing RAID10 logical volumes. To create a RAID10 logical volume, like the other RAID types, specify the segment type as follows: ~]# lvcreate --type raid10 -m 1 -i 2 -L 1G -n lv vg Note that the -m and -i arguments behave in the same way they would for other segment types. That is, -i is the total number of stripes while -m is the number of (additional) copies (that is, -m 1 -i 2 gives 2 stripes on top of 2-way mirrors).
Story Points: ---
Clone Of:
: 857209 (view as bug list)
Last Closed: 2013-02-21 03:13:08 EST
Type: Bug
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

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Description Jonathan Earl Brassow 2012-07-30 18:10:53 EDT
MD has the capability to do RAID10.  This is not simply stacking one segment type upon another - it is an integrated system that allows for many RAID10-like permutations.

This bug is a feature request for LVM to support the most basic variant of RAID10 - striped 2-way mirrors.
Comment 1 Jonathan Earl Brassow 2012-07-30 18:13:49 EDT

Simply put, perform all the tests on a RAID10 LV that are performed on a RAID1 or RAID4/5/6 LV.  This includes, but shouldn't be limited to:
1) Create RAID10 LV
2) Remove RAID10 LV
3) Resize RAID10 LV
4) Data consistency checking
5) Device failure testing
Comment 3 Corey Marthaler 2012-08-01 11:29:07 EDT
Adding QA ack for 6.4. 

Devel will need to provide unit testing results however before this bug can be
ultimately verified by QA.
Comment 4 Jonathan Earl Brassow 2012-09-04 12:16:33 EDT
LVM test suite passes with the following changes made to test this new feature:

- creation of RAID10 LVs  [lvcreate-raid.sh]
-- does not allow more than 2-way mirror
-- does allow more than 2-way stripe

- replacement of devices  [lvconvert-raid.sh]
-- replacement of any single device succeeds (while in-sync)
-- replacement of more than 1 dev in a mirror group fails
-- replacement of 1 dev from each mirror group will succeed

- resize LV [lvresize-raid.sh]
-- extend LV
-- reduce LV

For consistency testing, I only made a file system on the LV, mounted it, and did kernel untars and removals.
Comment 5 Jonathan Earl Brassow 2012-09-04 17:52:04 EDT
commit 4047e4dfb16175daec348bf44032c02181bd4c70
Author: Jonathan Brassow <jbrassow@redhat.com>
Date:   Fri Aug 24 15:34:19 2012 -0500

    RAID:  Add support for RAID10
    This patch adds support for RAID10.  It is not the default at this
    stage.  The user needs to specify '--type raid10' if they would like
    RAID10 instead of stacked mirror over stripe.
Comment 11 Nenad Peric 2013-01-22 05:17:32 EST
Ran both black_bird and raid_sanity test for 3 iterations without issues. 

I am marking this as verified even though there are some hickups with the whole mirrored stripe leg failuire of raid10 (which effectively kills raid10, as expected but could maybe be 'more graceful').

Verified with:

Comment 12 errata-xmlrpc 2013-02-21 03:13:08 EST
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.


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