i did just that (sudo reboot) and logs + persistence data of the last days are lost.
made another reboot and previous logs of today also vanished.
another try with “sudo shutdown -r”, same result, all data from 2020-07-11 until “before reboot” are lost.
log:
zram-config stop 2020-07-16-11:30:43
ztab remove log /zram2 /var/log /log.bind
/zram2
Warning: Stopping rsyslog.service, but it can still be activated by:
syslog.socket
umount: /var/log (overlay2) unmounted
overlay --lowerdir=/opt/zram/log.bind --upperdir=/opt/zram/zram2/upper
Upper directory not specified.
Try './overlay --help' for more information.
ztab remove dir /zram1 /var/lib/openhab2/persistence /persistence.bind
/zram1
umount: /var/lib/openhab2/persistence (overlay1) unmounted
overlay --lowerdir=/opt/zram/persistence.bind --upperdir=/opt/zram/zram1/upper
Upper directory not specified.
Try './overlay --help' for more information.
ztab remove swap /zram0 zram-config0
/dev/zram0 removed
'/usr/local/share/zram-config/zram-device-list.rev' wurde entfernt
'/usr/local/share/zram-config/zram-device-list' wurde entfernt
zram-config start 2020-07-16-11:30:56
ztab create swap lz4 200M 600M 75 0 90
insmod /lib/modules/4.19.118-v7l+/kernel/mm/zsmalloc.ko
insmod /lib/modules/4.19.118-v7l+/kernel/drivers/block/zram/zram.ko
zram0 created comp_algorithm=lz4 mem_limit=200M disksize=600M
Setting up swapspace version 1, size = 600 MiB (629141504 bytes)
LABEL=zram-config0, UUID=e759bb49-455d-498c-a3fc-2306348745e1
swapon: /dev/zram0: found signature [pagesize=4096, signature=swap]
swapon: /dev/zram0: pagesize=4096, swapsize=629145600, devsize=629145600
swapon /dev/zram0
vm.page-cluster = 0
vm.swappiness = 90
ztab create dir lz4 150M 500M /var/lib/openhab2/persistence /persistence.bind
dirPerm /var/lib/openhab2/persistence 775 110:115
mount: /var/lib/openhab2/persistence bound on /opt/zram/persistence.bind.
mount: /opt/zram/persistence.bind propagation flags changed.
dirMountOpt rw,noatime dirFsType ext4
zram1 created comp_algorithm=lz4 mem_limit=150M disksize=500M
mke2fs 1.44.5 (15-Dec-2018)
fs_types for mke2fs.conf resolution: 'ext4', 'small'
Discarding device blocks: done
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
128000 inodes, 128000 blocks
6400 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=132120576
4 block groups
32768 blocks per group, 32768 fragments per group
32000 inodes per group
Filesystem UUID: 7cc07125-3e9b-4bff-b2e2-18f679dfe0dd
Superblock backups stored on blocks:
32768, 98304
Allocating group tables: done
Writing inode tables: done
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done
mount: /dev/zram1 mounted on /opt/zram/zram1.
mount: overlay1 mounted on /var/lib/openhab2/persistence.
ztab create log lzo 150M 500M /var/log /log.bind
Warning: Stopping rsyslog.service, but it can still be activated by:
syslog.socket
dirPerm /var/log 755 0:0
mount: /var/log bound on /opt/zram/log.bind.
mount: /opt/zram/log.bind propagation flags changed.
dirMountOpt rw,noatime dirFsType ext4
zram2 created comp_algorithm=lzo mem_limit=150M disksize=500M
mke2fs 1.44.5 (15-Dec-2018)
fs_types for mke2fs.conf resolution: 'ext4', 'small'
Discarding device blocks: done
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
Stride=0 blocks, Stripe width=0 blocks
128000 inodes, 128000 blocks
6400 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=132120576
4 block groups
32768 blocks per group, 32768 fragments per group
32000 inodes per group
Filesystem UUID: bf2d6042-9f63-4e96-9e0c-b401ef546047
Superblock backups stored on blocks:
32768, 98304
Allocating group tables: done
Writing inode tables: done
Creating journal (4096 blocks): done
Writing superblocks and filesystem accounting information: done
mount: /dev/zram2 mounted on /opt/zram/zram2.
mount: overlay2 mounted on /var/log.
createZlog no oldlog dir in ztab
zram-config stop 2020-07-16-11:45:20
ztab remove log /zram2 /var/log /log.bind
/zram2
Warning: Stopping rsyslog.service, but it can still be activated by:
syslog.socket
umount: /var/log (overlay2) unmounted
overlay --lowerdir=/opt/zram/log.bind --upperdir=/opt/zram/zram2/upper
Upper directory not specified.
Try './overlay --help' for more information.
ztab remove dir /zram1 /var/lib/openhab2/persistence /persistence.bind
/zram1
umount: /var/lib/openhab2/persistence (overlay1) unmounted
overlay --lowerdir=/opt/zram/persistence.bind --upperdir=/opt/zram/zram1/upper
Upper directory not specified.
Try './overlay --help' for more information.
ztab remove swap /zram0 zram-config0
/dev/zram0 removed
'/usr/local/share/zram-config/zram-device-list.rev' wurde entfernt
'/usr/local/share/zram-config/zram-device-list' wurde entfernt
zramctl
gives no output.
i am 100% sure that i didn’t mess with anything zram related in the last days…
please help 
edit: is this / could this be related?
[12:06:52] openhabian@OHab2:~$ sudo systemctl restart openhab2
Warning: The unit file, source configuration file or drop-ins of openhab2.service changed on disk. Run 'systemctl daemon-reload' to reload units.
(systemctl daemon-reload doesn’t help)