For some reason ZFS was not mounting at startup. Remove the /home/ directory created by my terminal session then executing sudo zfs mount home and everything is back
My apologies for sounding like a less than well-informed sysadmin - this machine is a black box we use, and has been very reliable. Support from official IT is lacking for this system. This 56 Core PowerEdge R930 is running Debian 8. I just did a package update, which include a new kernel version (SMP Debian 3.16.57-2). This I have done before with no issues at all. After rebooting, the /home directory has gone MIA. All user directories are missing.  When I logged in via ssh, a directory was created for my account under /home, but the directory is empty and other user directories are present. /home is not a separate mount point in /etc/fstab Looking at syslog I see the following, which seems odd. It seems to be "probing" the SCSI disks and not finding a valid filessystem. Jul 30 08:53:49 sdiser001 systemd[1]: Mounted /performance.Jul 30 08:53:49 sdiser001 systemd[1]: Mounted /boot.Jul 30 08:53:49 sdiser001 systemd[1]: Mounted /.Jul 30 08:53:49 sdiser001 systemd[1]: Started File System Check on /dev/disk/by-uuid/0970214b-6be7-45ad-a25c-b3a869aa5e7a.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /dev/disk/by-uuid/0970214b-6be7-45ad-a25c-b3a869aa5e7a.Jul 30 08:53:49 sdiser001 systemd[1]: Created slice system-systemd\x2dfsck.slice.Jul 30 08:53:49 sdiser001 systemd[1]: Started File System Check on /dev/disk/by-uuid/2bea9f2e-a2bc-4025-924d-8bb639a79ab3.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /dev/disk/by-uuid/2bea9f2e-a2bc-4025-924d-8bb639a79ab3.Jul 30 08:53:49 sdiser001 systemd[1]: Reached target Network is Online.Jul 30 08:53:49 sdiser001 systemd[1]: Started LSB: RPC portmapper replacement.Jul 30 08:53:49 sdiser001 systemd[1]: Reached target RPC Port Mapper.Jul 30 08:53:49 sdiser001 systemd[1]: Activated swap /dev/disk/by-uuid/3f2dbcf9-b31e-41ab-8b52-5ed074dc197d.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /dev/disk/by-uuid/3f2dbcf9-b31e-41ab-8b52-5ed074dc197d.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /sys/devices/virtual/block/md2.Jul 30 08:53:49 sdiser001 systemd[1]: Started MD array monitor.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /dev/md2.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /dev/disk/by-id/md-name-sdiser001:2.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /dev/disk/by-id/md-uuid-1aea99bd:dc4cb79a:be6df49d:81f35692.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /dev/md/2.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /sys/devices/virtual/block/md3.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /dev/md3.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /dev/disk/by-id/md-name-sdiser001:3.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /dev/disk/by-id/md-uuid-11307d53:7651b679:4b5ea8b6:03383867.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /dev/md/3.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /sys/devices/virtual/block/md5.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /dev/md5.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /dev/disk/by-id/md-name-sdiser001:5.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /dev/disk/by-id/md-uuid-6c04f9bf:b337d107:23fcdcfb:ef80a381.Jul 30 08:53:49 sdiser001 systemd[1]: Found device /dev/md/5.Jul 30 08:53:49 sdiser001 systemd[1]: Activated swap /dev/md2.Jul 30 08:53:49 sdiser001 systemd[1]: Activated swap /dev/disk/by-id/md-name-sdiser001:2.Jul 30 08:53:49 sdiser001 systemd[1]: Activated swap /dev/disk/by-id/md-uuid-1aea99bd:dc4cb79a:be6df49d:81f35692.Jul 30 08:53:49 sdiser001 systemd[1]: Activated swap /dev/md/2.Jul 30 08:55:31 sdiser001 rsyslogd-2007: action 'action 17' suspended, next retry is Mon Jul 30 08:56:01 2018 [try [URL] ]Jul 30 09:03:21 sdiser001 os-prober: debug: running /usr/lib/os-probes/10zvol-test on /dev/sda1Jul 30 09:03:21 sdiser001 os-prober: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sda1Jul 30 09:03:21 sdiser001 os-prober: debug: running /usr/lib/os-probes/10zvol-test on /dev/sda9Jul 30 09:03:21 sdiser001 os-prober: debug: running /usr/lib/os-probes/50mounted-tests on /dev/sda9Jul 30 09:03:21 sdiser001 kernel: [7686358.914955] EXT4-fs (sda9): VFS: Can't find ext4 filesystemJul 30 09:03:21 sdiser001 kernel: [7686358.917508] EXT4-fs (sda9): VFS: Can't find ext4 filesystemJul 30 09:03:21 sdiser001 kernel: [7686358.920091] EXT4-fs (sda9): VFS: Can't find ext4 filesystem etc ( more like this)  
PowerEdge R930, /home gone MIA after Debian 8 update