[linux-lvm] Having duplicate PV problems, think there's a bug in LVM2 md component detection

[go0ogl3]

I'm anly a begginer at lvm but...

On Sat, 26 Feb 2005 15:30:08 -0500, Ron Watkins <linux-lvm at malor.com> wrote:
> I'm sorry if this is a FAQ or if I'm being stupid.  I saw some mentions to
> this problem on the old mailing list, but it didn't seem to quite cover what
> I'm seeing, and I don't see an archive for this list yet.  (and what on
> earth happened to the old list, anyway?)
> 
> My problem is this:  I'm setting up a software RAID5 across 5 IDE drives.
> I'm running Debian Unstable, using kernel 2.6.8-2-k7.   I HAVE set
> md_component_detection to 1 in lvm.conf, and I wiped the drives after
> changing this setting.
> 
> I originally set it up as a four-drive RAID, via a 3Ware controller, so my
> original devices were sdb, sdc, sdd, and sde. (the machine also has a
> hardware raid on an ICP Vortex SCSI controller: this is sda.)    In this
> mode, it set up and built perfectly.  LVM worked exactly as I expected it
> to.  I had a test volume running.  All the queries and volume management
> worked exactly correctly.  All was well.
> 
> So then I tried to add one more drive via the motherboard IDE controller, on
> /dev/hda.  (note that I stopped the array, wiped the first and last 100 megs
> on the drives, and rebuilt. ).  That's when the problems started.  The RAID
> itself seems to build and work just fine, although I haven't waited for the
> entire 6 or so hours it will take to completely finish.  Build speed is
> good, everything seems normal.  But LVM blows up badly in this
> configuration.
> 
> When I do a pvcreate on /dev/md0, it succeeds... but if I do a pvdisplay I
> get a bunch of complaints:
> 
> jeeves:/etc/lvm# pvdisplay
>  Found duplicate PV y8pYTtAg0W703Sc8Wiy79mcWU3gHmCFc: using /dev/sde not
> /dev/hda
>  Found duplicate PV y8pYTtAg0W703Sc8Wiy79mcWU3gHmCFc: using /dev/sde not
> /dev/hda

I think you have 2 PV's with the same UUID and that's the problem. You
can even move the drives letters around (hda or sda) as I think it
does not matter for lvm. The only thing it counts it's the "UUID"  of
the PV.

You should use pvcreate again on /dev/hda so your last added drive
should have different UUID.

>  --- NEW Physical volume ---
>  PV Name               /dev/hda
>  VG Name
>  PV Size               931.54 GB
>  Allocatable           NO
>  PE Size (KByte)       0
>  Total PE              0
>  Free PE               0
>  Allocated PE          0
>  PV UUID               y8pYTt-Ag0W-703S-c8Wi-y79m-cWU3-gHmCFc
> 
> It seems to think that /dev/hda is where the PV is, rather than /dev/md0.
> 
> (Note, again, I *HAVE* turned the md_component_detection to 1 in lvm.conf!!)
> 
> I have erased, using dd, the first and last 100 megs or so on every drive,
> and I get exactly the same results every time... even with all RAID and LVM
> blocks erased, if I use this list of drives:
> 
> /dev/hda
> /dev/sdb
> /dev/sdc
> /dev/sdd
> /dev/sde
> 
> with the linux MD driver, LVM does not seem to work properly.  I think the
> component detection is at least a little buggy.  This is what my
> /proc/mdstat looks like:
> 
> jeeves:/etc/lvm# cat /proc/mdstat
> Personalities : [raid5]
> md0 : active raid5 sde[5] sdd[3] sdc[2] sdb[1] hda[0]
>      976793600 blocks level 5, 128k chunk, algorithm 2 [5/4] [UUUU_]
>      [=>...................]  recovery =  6.2% (15208576/244198400)
> finish=283.7min speed=13448K/sec
> unused devices: <none>
> 
> I realize that using both IDE and SCSI drives in the same array is
> unusual... but I'm not really using SCSI drives, they just look like that
> because of the 3Ware controller.
> 
> Again, this works FINE as long as I just use the (fake) SCSI devices.. it
> doesn't wonk out until I add in /dev/hda.
> 
> Any suggestions?  Is this a bug?
> 
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