FreeBSD 11.0, Xfce, and system drive cloning breaks Xfce applications

[David Christensen]

freebsd-xfce:

I have a computer with Intel DQ67SW motherboard, Intel Core i7-2600S 
CPU, 8 GB RAM, 16 GB SSD.


I installed:

FreeBSD-11.0-RELEASE-i386-memstick.img


I selected MBR partitioning and encrypted ZFS on root during installation.


toor at freebsd:/root # freebsd-version; uname -a
11.0-RELEASE-p7
FreeBSD freebsd 11.0-RELEASE-p1 FreeBSD 11.0-RELEASE-p1 #0 r306420: Thu 
Sep 29 03:40:55 UTC 2016 
root at releng2.nyi.freebsd.org:/usr/obj/usr/src/sys/GENERIC  i386

toor at freebsd:/root # pkg info xorg | head -n 1
xorg-7.7_2

toor at freebsd:/root # pkg info xfce | head -n 1
xfce-4.12_1

toor at freebsd:/root # gpart show
=>      63  31277169  ada0  MBR  (15G)
         63         1        - free -  (512B)
         64  31277160     1  freebsd  [active]  (15G)
   31277224         8        - free -  (4.0K)

=>       0  31277160  ada0s1  BSD  (15G)
          0   4194304       1  freebsd-zfs  (2.0G)
    4194304   4194304       2  freebsd-swap  (2.0G)
    8388608  22888544       4  freebsd-zfs  (11G)
   31277152         8          - free -  (4.0K)

toor at freebsd:/root # zpool list
NAME       SIZE  ALLOC   FREE  EXPANDSZ   FRAG    CAP  DEDUP  HEALTH ALTROOT
bootpool  1.98G   101M  1.89G         -     6%     4%  1.00x  ONLINE  -
zroot     10.9G  4.30G  6.58G         -    33%    39%  1.00x  ONLINE  -

toor at freebsd:/root # zfs list
NAME                 USED  AVAIL  REFER  MOUNTPOINT
bootpool             101M  1.82G  99.4M  /bootpool
zroot               4.30G  6.24G    96K  /zroot
zroot/ROOT          2.68G  6.24G    96K  none
zroot/ROOT/default  2.68G  6.24G  2.68G  /
zroot/tmp            164K  6.24G   164K  /tmp
zroot/usr           1.61G  6.24G    96K  /usr
zroot/usr/home       399M  6.24G   399M  /usr/home
zroot/usr/ports      641M  6.24G   641M  /usr/ports
zroot/usr/src        609M  6.24G   609M  /usr/src
zroot/var            812K  6.24G    96K  /var
zroot/var/audit       96K  6.24G    96K  /var/audit
zroot/var/crash       96K  6.24G    96K  /var/crash
zroot/var/log        308K  6.24G   308K  /var/log
zroot/var/mail       120K  6.24G   120K  /var/mail
zroot/var/tmp         96K  6.24G    96K  /var/tmp


If I use 'dd' to take an image of the system drive (using Debian 7 on a 
Pentium D 945 computer):

2017-01-28 13:44:37 root at p43200 ~
# parted /dev/sdb u s p free
Model: ATA SAMSUNG SSD UM41 (scsi)
Disk /dev/sdb: 31277232s
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start      End        Size       Type     File system  Flags
         63s        63s        1s                  Free Space
  1      64s        31277223s  31277160s  primary  zfs          boot
         31277224s  31277231s  8s                  Free Space

2017-01-28 13:44:55 root at p43200 ~
# cd /mnt/q/image/holgerdanske.com/freebsd/

2017-01-28 13:48:05 root at p43200 /mnt/q/image/holgerdanske.com/freebsd
# time dd if=/dev/sdb count=31277224 | gzip | tee 
i72600s-20170128-1346-freebsd-11.0-release-i386-op.img.gz | sha256sum -b 
 > i72600s-20170128-1346-freebsd-11.0-release-i386-op.img.gz.sha256
31277224+0 records in
31277224+0 records out
16013938688 bytes (16 GB) copied, 1032.32 s, 15.5 MB/s

real    17m12.330s
user    12m7.961s
sys     1m42.726s


And put the image onto a 60 GB SSD:

2017-01-28 20:56:58 root at p43200 /mnt/q/image/holgerdanske.com/freebsd
# time zcat i72600s-20170128-1346-freebsd-11.0-release-i386-op.img.gz > 
/dev/sdb

real    3m42.036s
user    1m35.854s
sys     0m27.406s

2017-01-28 21:01:07 root at p43200 /mnt/q/image/holgerdanske.com/freebsd
# parted /dev/sdb u s p free
Model: ATA INTEL SSDSC2CW06 (scsi)
Disk /dev/sdb: 117231408s
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start      End         Size       Type     File system  Flags
         63s        63s         1s                  Free Space
  1      64s        31277223s   31277160s  primary  zfs          boot
         31277224s  117231407s  85954184s           Free Space


When I boot the cloned drive in the same computer, Xfce applications 
refuse to start.  For example, selecting Application Menu -> Terminal 
Emulator issues a pop-up:

         Failed to execute default Terminal Emulator.

         Input/output error.


Switching to the console (Ctrl+Alt+F1), I see the following error messages:

         vm_fault: pager read error: pid 1023 (python2.7)
         vm_fault: pager read error: pid 1040 (xfce4-terminal)


What is the problem?


How do I fix it?


TIA,

David