ZFS snapshot - rollback problem

[Christoph Brinkhaus]

On Thu, Sep 10, 2020 at 04:18:39PM +0200, Ludovit Koren wrote:
> Hi,
> 
> I have the following configuration:
> 
> ~>uname -a
> FreeBSD XxX 11.3-STABLE FreeBSD 11.3-STABLE #1 r354607: Mon Nov 11
> 12:19:28 CET 2019     root at jedi:/usr/obj/usr/src/sys/HP  amd64
> ~>zfs list
> NAME              USED  AVAIL  REFER  MOUNTPOINT
> zroot             244G      0  10.7G  /mnt
> zroot/Centos8    6.80G  4.13G  2.67G  -
> zroot/msw7       44.9G  25.8G  19.1G  -
> zroot/swapdisk0  40.8G  20.6G  20.2G  -
> zroot/usr         131G      0  50.9G  /usr
> zroot/usr/home   80.1G      0  80.1G  /usr/home
> zroot/var        9.94G      0  9.94G  /var
> 
> After zfs snapshot, which I did on the root, I got:
> ~>zfs list -t snapshot
> NAME                     USED  AVAIL  REFER  MOUNTPOINT
> zroot at 200909               1K      -  10.7G  -
> zroot/Centos8 at 200909       1K      -  2.67G  -
> zroot/msw7 at 200909          1K      -  19.1G  -
> zroot/swapdisk0 at 200909      0      -  20.2G  -
> zroot/usr at 200909           1K      -  50.9G  -
> zroot/usr/home at 200909      1K      -  80.1G  -
> zroot/var at 200909           1K      -  9.94G  -
> 
> i.e. whole filesystem is read only. I am not able to do neither
> rollback, nor destroy of the snapshot. Is there any possibility to
> reset the filesystem to the read-write mode?

I do not see there if it is read only or not.
To change the readyonly property:
zfs set readonly=off

Mount to make it effective:
zfs mount -a 
> 
> Any help is greatly appreciated.
I hope my notes are correct and help you.

Kind regards,
Christoph