I've experienced apparent data loss, and hoping someone out there can
help rescue my data, or at least tell me what went wrong so that I don't
have a repeat event. I first asked this question on linux-lvm, but the
folks there seemed to think it pertained more to RAID than to LVM.
I was setting up a new server running Ubuntu's Hardy Heron release.
`uname -a` reports:
Linux sherwood 2.6.24-16-server #1 SMP Thu Apr 10 13:58:00 UTC 2008 i686 GNU/Linux
I initially created an md RAID5 device with only two components
(matching 320 GB SATA HDDs). I created a single LVM Physical Volume
using the entirety of that md device (320 GB), and then created several
LVM Logical Volumes for different filesystems (all ext3). This was done
using the Ubuntu installer. After installing I used lvresize to
increase the size of a few of the Logical Volumes. These filesystems
hold data that is not a critical part of the system (mail, music, video,
etc.), but still important to me.
I then copied data onto one of those filesystems (the original source of
the data is no longer available). I then added a third drive to the md
device, which brought the total to 2 active devices and 1 spare device.
I then grew the number of devices to 3 and waited for the reshape to
finish (increasing the capacity to 640 GB). I bumped the values in
/proc/sys/dev/raid/ so that I wouldn't have to wait as long.
Now that the reshaping has completed, LVM can't find the physical volume
on that device anymore. I tried rebooting the system, but the problem
remained. Checking /proc/mdstat shows that the md device is up and
healthy. The pvdisplay command only shows my other Physical Volume (for
the IDE drives). I found the pvck command and ran that on the md
device, and it states that there is no LVM label on the device.
It is my understanding that the steps I outlined should have worked.
I planned to follow them with pvresize, then lvresize, then umount,
resize2fs, and mount again. I've seen this procedure outlined a few
different places, including at
http://gentoo-wiki.info/Resize_LVM2_on_RAID5.
Did I do something wrong? Is there anyway to rescue my data? If
there's no way of saving the data, I'd at least like to figure out what
happened in the first place.
Thank you. Your thoughtfulness and help is appreciated.
--
Bob Bell
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