[linux-lvm] Setting up LVM cache causes crash

* [linux-lvm] Setting up LVM cache causes crash
@ 2014-08-25 16:45 Elvin Cako
  2014-09-02 22:00 ` Brassow Jonathan
  0 siblings, 1 reply; 18+ messages in thread
From: Elvin Cako @ 2014-08-25 16:45 UTC (permalink / raw)
  To: linux-lvm; +Cc: data

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Hello,

Kernel:

3.10.0-123.6.3.el7.x86_64 #1 SMP Wed Aug 6 21:12:36 UTC 2014 x86_64 x86_64
x86_64 GNU/Linux

Issue:
In trying to set up the new LVM caching, I've run into some issues. I have
followed the steps in the lvm manual:

       0. Create an origin LV we wish to cache (yours may already exist)

       # lvcreate -L 10G -n lvx vg /dev/slow

       Already Exists

       1. Create a cache data LV

       # lvcreate -L 1G -n lvx_cache vg /dev/fast

       [root@cheeseboy mysql_python]# vgextend dataraid10 /dev/md30
/dev/md31 /dev/md32 /dev/md33 /dev/md34

       [root@cheeseboy mysql_python]# lvcreate -i 5 -I 32 -l 100%FREE -n
dataraid10ssdcache dataraid10

  Logical volume "dataraid10ssdcache" created

       2. Create a cache metadata LV

       # lvcreate -L 8M -n lvx_cache_meta vg /dev/fast

       [root@cheeseboy mysql_python]# vgextend dataraid10 /dev/md35

       [root@cheeseboy mysql_python]# lvcreate -i 1 -I 32 -L 20G -n
dataraid10metadata dataraid10

  Ignoring stripesize argument with single stripe

  Logical volume "dataraid10metadata" created

       3. Create a cache pool LV specifying cache mode "writethrough"

       # lvconvert --type cache-pool --poolmetadata vg/lvx_cache_meta \

            --cachemode writethrough vg/lvx_cache

       [root@cheeseboy mysql_python]# lvconvert --type cache-pool
--poolmetadata dataraid10/dataraid10metadata --cachemode writethrough
dataraid10/dataraid10ssdcache

  Converted dataraid10/dataraid10ssdcache to cache pool.

       4. Create a cache LV by combining the cache pool LV and origin LV

       # lvconvert --type cache --cachepool vg/lvx_cache vg/lvx

       [root@cheeseboy mysql_python]# lvconvert --type cache --cachepool
dataraid10/dataraid10ssdcache dataraid10/dataraid10one

  dataraid10/dataraid10one is now cached.

[root@cheeseboy mysql_python]# vgchange -a y dataraid10  [==> causes crash]

All the above steps seem to run perfectly fine. The issue arises when I try
to activate the volume group after. Every time an activation is attempted
the box crashes. Everything works fine once I revert back to before the
cache was implemented.

Additional info:

*PVSCAN*
Not sure whether related but running pvscan results in the following:

[root@cheeseboy mysql_python]# pvscan

  No device found for PV gjmSco-2SdO-5uwL-lSQD-nwYo-fUE1-REYBQ4.

  No device found for PV OnYrCH-Qfv0-AMdo-7IKv-bd6L-FgMk-bvQALX.

  No device found for PV cpuPLk-GZWG-hcz4-4Byc-jFVH-d2o3-zT1Yn1.

  No device found for PV dzvkpM-CLSx-UdJG-RUP4-aazN-Ew8Y-z5ePLc.

  No device found for PV 0c7AOC-Ulj3-tHKs-XfLz-1Mgc-AzEn-dOFQJx.

  No device found for PV HDPYYO-Us7J-wpfM-718x-D32U-IEXg-J8tDTa.

  No device found for PV h6F3OG-u3Bm-yjwX-rDe3-xfvm-KxtW-bZa0Zv.

  No device found for PV R0rajR-2os4-3z6g-TWur-6NR5-B5SE-4frydn.

  No device found for PV 7aNXGY-uEOp-54Vc-GWZl-yhEn-DGOG-D8IqDe.

  .

  .

  .

lvdisplay does not show logical volumes:

[root@cheeseboy mysql_python]# lvdisplay